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Rico-Porras JM, Mora P, Palomeque T, Montiel EE, Cabral-de-Mello DC, Lorite P. Heterochromatin Is Not the Only Place for satDNAs: The High Diversity of satDNAs in the Euchromatin of the Beetle Chrysolina americana (Coleoptera, Chrysomelidae). Genes (Basel) 2024; 15:395. [PMID: 38674330 PMCID: PMC11049206 DOI: 10.3390/genes15040395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/16/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024] Open
Abstract
The satellitome of the beetle Chrysolina americana Linneo, 1758 has been characterized through chromosomal analysis, genomic sequencing, and bioinformatics tools. C-banding reveals the presence of constitutive heterochromatin blocks enriched in A+T content, primarily located in pericentromeric regions. Furthermore, a comprehensive satellitome analysis unveils the extensive diversity of satellite DNA families within the genome of C. americana. Using fluorescence in situ hybridization techniques and the innovative CHRISMAPP approach, we precisely map the localization of satDNA families on assembled chromosomes, providing insights into their organization and distribution patterns. Among the 165 identified satDNA families, only three of them exhibit a remarkable amplification and accumulation, forming large blocks predominantly in pericentromeric regions. In contrast, the remaining, less abundant satDNA families are dispersed throughout euchromatic regions, challenging the traditional association of satDNA with heterochromatin. Overall, our findings underscore the complexity of repetitive DNA elements in the genome of C. americana and emphasize the need for further exploration to elucidate their functional significance and evolutionary implications.
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Affiliation(s)
- José M. Rico-Porras
- Department of Experimental Biology, Genetics Area, University of Jaén, Paraje las Lagunillas s/n, 23071 Jaén, Spain; (J.M.R.-P.); (P.M.); (T.P.)
| | - Pablo Mora
- Department of Experimental Biology, Genetics Area, University of Jaén, Paraje las Lagunillas s/n, 23071 Jaén, Spain; (J.M.R.-P.); (P.M.); (T.P.)
| | - Teresa Palomeque
- Department of Experimental Biology, Genetics Area, University of Jaén, Paraje las Lagunillas s/n, 23071 Jaén, Spain; (J.M.R.-P.); (P.M.); (T.P.)
| | - Eugenia E. Montiel
- Department of Biology, Genetics, Faculty of Sciences, Autonomous University of Madrid, 28049 Madrid, Spain;
- Center for Research in Biodiversity and Global Change, Autonomous University of Madrid, 28049 Madrid, Spain
| | - Diogo C. Cabral-de-Mello
- Department of General and Applied Biology, Institute of Biosciences/IB, UNESP—São Paulo State University, Rio Claro 13506-900, SP, Brazil;
| | - Pedro Lorite
- Department of Experimental Biology, Genetics Area, University of Jaén, Paraje las Lagunillas s/n, 23071 Jaén, Spain; (J.M.R.-P.); (P.M.); (T.P.)
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2
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Estevez-Castro CF, Rodrigues MF, Babarit A, Ferreira FV, de Andrade EG, Marois E, Cogni R, Aguiar ERGR, Marques JT, Olmo RP. Neofunctionalization driven by positive selection led to the retention of the loqs2 gene encoding an Aedes specific dsRNA binding protein. BMC Biol 2024; 22:14. [PMID: 38273313 PMCID: PMC10809485 DOI: 10.1186/s12915-024-01821-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Mosquito borne viruses, such as dengue, Zika, yellow fever and Chikungunya, cause millions of infections every year. These viruses are mostly transmitted by two urban-adapted mosquito species, Aedes aegypti and Aedes albopictus. Although mechanistic understanding remains largely unknown, Aedes mosquitoes may have unique adaptations that lower the impact of viral infection. Recently, we reported the identification of an Aedes specific double-stranded RNA binding protein (dsRBP), named Loqs2, that is involved in the control of infection by dengue and Zika viruses in mosquitoes. Preliminary analyses suggested that the loqs2 gene is a paralog of loquacious (loqs) and r2d2, two co-factors of the RNA interference (RNAi) pathway, a major antiviral mechanism in insects. RESULTS Here we analyzed the origin and evolution of loqs2. Our data suggest that loqs2 originated from two independent duplications of the first double-stranded RNA binding domain of loqs that occurred before the origin of the Aedes Stegomyia subgenus, around 31 million years ago. We show that the loqs2 gene is evolving under relaxed purifying selection at a faster pace than loqs, with evidence of neofunctionalization driven by positive selection. Accordingly, we observed that Loqs2 is localized mainly in the nucleus, different from R2D2 and both isoforms of Loqs that are cytoplasmic. In contrast to r2d2 and loqs, loqs2 expression is stage- and tissue-specific, restricted mostly to reproductive tissues in adult Ae. aegypti and Ae. albopictus. Transgenic mosquitoes engineered to express loqs2 ubiquitously undergo developmental arrest at larval stages that correlates with massive dysregulation of gene expression without major effects on microRNAs or other endogenous small RNAs, classically associated with RNA interference. CONCLUSIONS Our results uncover the peculiar origin and neofunctionalization of loqs2 driven by positive selection. This study shows an example of unique adaptations in Aedes mosquitoes that could ultimately help explain their effectiveness as virus vectors.
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Affiliation(s)
- Carlos F Estevez-Castro
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Murillo F Rodrigues
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403-5289, USA
| | - Antinéa Babarit
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Flávia V Ferreira
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Elisa G de Andrade
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Eric Marois
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Rodrigo Cogni
- Department of Ecology, Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
| | - Eric R G R Aguiar
- Department of Biological Science, Center of Biotechnology and Genetics, State University of Santa Cruz, Ilhéus, 45662-900, Brazil
| | - João T Marques
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France.
| | - Roenick P Olmo
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France.
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3
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Biedler JK, Aryan A, Qi Y, Wang A, Martinson EO, Hartman DA, Yang F, Sharma A, Morton KS, Potters M, Chen C, Dobson SL, Ebel GD, Kading RC, Paulson S, Xue RD, Strand MR, Tu Z. On the Origin and Evolution of the Mosquito Male-determining Factor Nix. Mol Biol Evol 2024; 41:msad276. [PMID: 38128148 PMCID: PMC10798136 DOI: 10.1093/molbev/msad276] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/02/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
The mosquito family Culicidae is divided into 2 subfamilies named the Culicinae and Anophelinae. Nix, the dominant male-determining factor, has only been found in the culicines Aedes aegypti and Aedes albopictus, 2 important arboviral vectors that belong to the subgenus Stegomyia. Here we performed sex-specific whole-genome sequencing and RNAseq of divergent mosquito species and explored additional male-inclusive datasets to investigate the distribution of Nix. Except for the Culex genus, Nix homologs were found in all species surveyed from the Culicinae subfamily, including 12 additional species from 3 highly divergent tribes comprising 4 genera, suggesting Nix originated at least 133 to 165 million years ago (MYA). Heterologous expression of 1 of 3 divergent Nix open reading frames (ORFs) in Ae. aegypti resulted in partial masculinization of genetic females as evidenced by morphology and doublesex splicing. Phylogenetic analysis suggests Nix is related to femaleless (fle), a recently described intermediate sex-determining factor found exclusively in anopheline mosquitoes. Nix from all species has a conserved structure, including 3 RNA-recognition motifs (RRMs), as does fle. However, Nix has evolved at a much faster rate than fle. The RRM3 of both Nix and fle are distantly related to the single RRM of a widely distributed and conserved splicing factor transformer-2 (tra2). The RRM3-based phylogenetic analysis suggests this domain in Nix and fle may have evolved from tra2 or a tra2-related gene in a common ancestor of mosquitoes. Our results provide insights into the evolution of sex determination in mosquitoes and will inform broad applications of mosquito-control strategies based on manipulating sex ratios toward nonbiting males.
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Affiliation(s)
- James K Biedler
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Azadeh Aryan
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Yumin Qi
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Aihua Wang
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ellen O Martinson
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Daniel A Hartman
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Fan Yang
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
| | - Atashi Sharma
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Katherine S Morton
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mark Potters
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Chujia Chen
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Genetics Bioinformatics and Computational Biology PhD program, Virginia Tech, Blacksburg, VA 24061, USA
| | - Stephen L Dobson
- Department of Entomology, University of Kentucky, Lexington, KY 40503, USA
- MosquitoMate, Inc., Lexington, KY 40502, USA
| | - Gregory D Ebel
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Rebekah C Kading
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Sally Paulson
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
| | - Rui-De Xue
- Anastasia Mosquito Control District, St. Augustine, FL 32092, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Genetics Bioinformatics and Computational Biology PhD program, Virginia Tech, Blacksburg, VA 24061, USA
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4
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Weng SC, Masri RA, Akbari OS. Advances and challenges in synthetic biology for mosquito control. Trends Parasitol 2024; 40:75-88. [PMID: 38000957 PMCID: PMC11064511 DOI: 10.1016/j.pt.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/26/2023]
Abstract
Mosquito-borne illnesses represent a significant global health peril, resulting in approximately one million fatalities annually. West Nile, dengue, Zika, and malaria are continuously expanding their global reach, driven by factors that escalate mosquito populations and pathogen transmission. Innovative control measures are imperative to combat these catastrophic ailments. Conventional approaches, such as eliminating breeding sites and using insecticides, have been helpful, but they face challenges such as insecticide resistance and environmental harm. Given the mounting severity of mosquito-borne diseases, there is promise in exploring innovative approaches using synthetic biology to bolster mosquitoes' resistance to pathogens, or even eliminate the mosquito vectors, as a means of control. This review outlines current strategies, future goals, and the importance of gene editing for global health defenses against mosquito-borne diseases.
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Affiliation(s)
- Shih-Che Weng
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reem A Masri
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Omar S Akbari
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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5
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Martí E, Larracuente AM. Genetic conflict and the origin of multigene families: implications for sex chromosome evolution. Proc Biol Sci 2023; 290:20231823. [PMID: 37909083 PMCID: PMC10618873 DOI: 10.1098/rspb.2023.1823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/10/2023] [Indexed: 11/02/2023] Open
Abstract
Sex chromosomes are havens for intragenomic conflicts. The absence of recombination between sex chromosomes creates the opportunity for the evolution of segregation distorters: selfish genetic elements that hijack different aspects of an individual's reproduction to increase their own transmission. Biased (non-Mendelian) segregation, however, often occurs at a detriment to their host's fitness, and therefore can trigger evolutionary arms races that can have major consequences for genome structure and regulation, gametogenesis, reproductive strategies and even speciation. Here, we review an emerging feature from comparative genomic and sex chromosome evolution studies suggesting that meiotic drive is pervasive: the recurrent evolution of paralogous sex-linked gene families. Sex chromosomes of several species independently acquire and co-amplify rapidly evolving gene families with spermatogenesis-related functions, consistent with a history of intragenomic conflict over transmission. We discuss Y chromosome features that might contribute to the tempo and mode of evolution of X/Y co-amplified gene families, as well as their implications for the evolution of complexity in the genome. Finally, we propose a framework that explores the conditions that might allow for recurrent bouts of fixation of drivers and suppressors, in a dosage-sensitive fashion, and therefore the co-amplification of multigene families on sex chromosomes.
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Affiliation(s)
- Emiliano Martí
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
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6
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Page N, Taxiarchi C, Tonge D, Kuburic J, Chesters E, Kriezis A, Kyrou K, Game L, Nolan T, Galizi R. Single-cell profiling of Anopheles gambiae spermatogenesis defines the onset of meiotic silencing and premeiotic overexpression of the X chromosome. Commun Biol 2023; 6:850. [PMID: 37582841 PMCID: PMC10427639 DOI: 10.1038/s42003-023-05224-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Understanding development and genetic regulation in the Anopheles gambiae germline is essential to engineer effective genetic control strategies targeting this malaria mosquito vector. These include targeting the germline to induce sterility or using regulatory sequences to drive transgene expression for applications such as gene drive. However, only very few germline-specific regulatory elements have been characterised with the majority showing leaky expression. This has been shown to considerably reduce the efficiency of current genetic control strategies, which rely on regulatory elements with more tightly restricted spatial and/or temporal expression. Meiotic silencing of the sex chromosomes limits the flexibility of transgene expression to develop effective sex-linked genetic control strategies. Here, we build on our previous study, dissecting gametogenesis into four distinct cell populations, using single-cell RNA sequencing to define eight distinct cell clusters and associated germline cell-types using available marker genes. We reveal overexpression of X-linked genes in a distinct cluster of pre-meiotic cells and document the onset of meiotic silencing of the X chromosome in a subcluster of cells in the latter stages of spermatogenesis. This study provides a comprehensive dataset, characterising the expression of distinct cell types through spermatogenesis and widening the toolkit for genetic control of malaria mosquitoes.
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Affiliation(s)
- Nicole Page
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Daniel Tonge
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| | - Jasmina Kuburic
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| | - Emily Chesters
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| | - Antonios Kriezis
- Department of Life Sciences, Imperial College London, London, UK
| | - Kyros Kyrou
- Department of Life Sciences, Imperial College London, London, UK
| | - Laurence Game
- Genomics Facility, MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
| | - Tony Nolan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Roberto Galizi
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK.
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7
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Kaufmann P, Wiberg RAW, Papachristos K, Scofield DG, Tellgren-Roth C, Immonen E. Y-Linked Copy Number Polymorphism of Target of Rapamycin Is Associated with Sexual Size Dimorphism in Seed Beetles. Mol Biol Evol 2023; 40:msad167. [PMID: 37479678 PMCID: PMC10414808 DOI: 10.1093/molbev/msad167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/03/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023] Open
Abstract
The Y chromosome is theorized to facilitate evolution of sexual dimorphism by accumulating sexually antagonistic loci, but empirical support is scarce. Due to the lack of recombination, Y chromosomes are prone to degenerative processes, which poses a constraint on their adaptive potential. Yet, in the seed beetle, Callosobruchus maculatus segregating Y linked variation affects male body size and thereby sexual size dimorphism (SSD). Here, we assemble C. maculatus sex chromosome sequences and identify molecular differences associated with Y-linked SSD variation. The assembled Y chromosome is largely euchromatic and contains over 400 genes, many of which are ampliconic with a mixed autosomal and X chromosome ancestry. Functional annotation suggests that the Y chromosome plays important roles in males beyond primary reproductive functions. Crucially, we find that, besides an autosomal copy of the gene target of rapamycin (TOR), males carry an additional TOR copy on the Y chromosome. TOR is a conserved regulator of growth across taxa, and our results suggest that a Y-linked TOR provides a male specific opportunity to alter body size. A comparison of Y haplotypes associated with male size difference uncovers a copy number variation for TOR, where the haplotype associated with decreased male size, and thereby increased sexual dimorphism, has two additional TOR copies. This suggests that sexual conflict over growth has been mitigated by autosome to Y translocation of TOR followed by gene duplications. Our results reveal that despite of suppressed recombination, the Y chromosome can harbor adaptive potential as a male-limited supergene.
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Affiliation(s)
- Philipp Kaufmann
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Uppsala, Sweden
| | - R Axel W Wiberg
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Uppsala, Sweden
- Ecology Division, Department of Zoology, Stockholm University, Stockholm, Sweden
| | | | - Douglas G Scofield
- Uppsala Multidisciplinary Center for Advanced Computational Science, Uppsala University, Uppsala, Sweden
| | - Christian Tellgren-Roth
- National Genomics Infrastructure, Uppsala Genome Center, SciLifeLab, BioMedical Centre, Uppsala University, Uppsala, Sweden
| | - Elina Immonen
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Uppsala, Sweden
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8
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Liang J, Bondarenko SM, Sharakhov IV, Sharakhova MV. Obtaining Polytene, Meiotic, and Mitotic Chromosomes from Mosquitoes for Cytogenetic Analysis. Cold Spring Harb Protoc 2022; 2022:591-598. [PMID: 35960616 DOI: 10.1101/pdb.prot107872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Chromosome visualization is a key step for developing cytogenetic maps and idiograms, analyzing inversion polymorphisms, and identifying mosquito species. Three types of chromosomes-polytene, mitotic, and meiotic-are used in cytogenetic studies of mosquitoes. Here, we describe a detailed method for obtaining high-quality polytene chromosome preparations from the salivary glands of larvae and the ovaries of females for Anopheles mosquitoes. We also describe how to obtain mitotic chromosomes from imaginal discs of fourth-instar larvae and meiotic chromosomes from the testes of male pupae for all mosquitoes. These chromosomes can be used for fluorescence in situ hybridization (FISH), a fundamental technique in cytogenetic research that is used for physical genome mapping, detecting chromosomal rearrangements, and studying chromosome organization.
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Affiliation(s)
- Jiangtao Liang
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA
| | - Simon M Bondarenko
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA.,Department of Genetics and Cell Biology, Tomsk State University, Tomsk 634050, Russia
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA.,Department of Genetics and Cell Biology, Tomsk State University, Tomsk 634050, Russia
| | - Maria V Sharakhova
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA .,Laboratory of Evolutionary Genomics of Insects, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
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9
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Kojin BB, Compton A, Adelman ZN, Tu Z. Selective targeting of biting females to control mosquito-borne infectious diseases. Trends Parasitol 2022; 38:791-804. [PMID: 35952630 PMCID: PMC9372635 DOI: 10.1016/j.pt.2022.05.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 10/18/2022]
Abstract
Mosquitoes are vectors for a number of infectious diseases. Only females feed on blood to provision for their embryos and, in doing so, transmit pathogens to the associated vertebrate hosts. Therefore, sex is an important phenotype in the context of genetic control programs, both for sex separation in the rearing facilities to avoid releasing biting females and for ways to distort the sex ratio towards nonbiting males. We review recent progress in the fundamental knowledge of sex determination and sex chromosomes in mosquitoes and discuss new methods to achieve sex separation and sex ratio distortion to help control mosquito-borne infectious diseases. We conclude by suggesting a few critical areas for future research.
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Affiliation(s)
- Bianca B Kojin
- Department of Entomology and Agrilife Research, Texas A&M University, College Station, TX, USA
| | - Austin Compton
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA; Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Zach N Adelman
- Department of Entomology and Agrilife Research, Texas A&M University, College Station, TX, USA.
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA; Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA.
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10
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Vitale M, Leo C, Courty T, Kranjc N, Connolly JB, Morselli G, Bamikole C, Haghighat-Khah RE, Bernardini F, Fuchs S. Comprehensive characterization of a transgene insertion in a highly repetitive, centromeric region of Anopheles mosquitoes. Pathog Glob Health 2022; 117:273-283. [PMID: 35861105 PMCID: PMC10081084 DOI: 10.1080/20477724.2022.2100192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The availability of the genomic sequence of the malaria mosquito Anopheles gambiae has in recent years sparked the development of transgenic technologies with the potential to be used as novel vector control tools. These technologies rely on genome editing that confer traits able to affect vectorial capacity. This can be achieved by either reducing the mosquito population or by making mosquitoes refractory to the parasite infection. For any genetically modified organism that is regarded for release, molecular characterization of the transgene and flanking sites are essential for their safety assessment and post-release monitoring. Despite great advancements, Whole-Genome Sequencing data are still subject to limitations due to the presence of repetitive and unannotated DNA sequences. Faced with this challenge, we describe a number of techniques that were used to identify the genomic location of a transgene in the male bias mosquito strain Ag(PMB)1 considered for potential field application. While the initial inverse PCR identified the most likely insertion site on Chromosome 3 R 36D, reassessment of the data showed a high repetitiveness in those sequences and multiple genomic locations as potential insertion sites of the transgene. Here we used a combination of DNA sequencing analysis and in-situ hybridization to clearly identify the integration of the transgene in a poorly annotated centromeric region of Chromosome 2 R 19D. This study emphasizes the need for accuracy in sequencing data for the genome of organisms of medical importance such as Anopheles mosquitoes and other tools available that can support genomic locations of transgenes.
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Affiliation(s)
- Matteo Vitale
- Department of Life Sciences, Imperial College London, London, UK
| | - Chiara Leo
- Polo d'Innovazione di Genomica, Genetica, e Biologia, Siena, Italy
| | - Thomas Courty
- Department of Infectious Diseases, King's College London, London, UK
| | - Nace Kranjc
- Department of Life Sciences, Imperial College London, London, UK
| | - John B Connolly
- Department of Life Sciences, Imperial College London, London, UK
| | - Giulia Morselli
- Department of Life Sciences, Imperial College London, London, UK
| | - Christopher Bamikole
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | | | | | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, UK
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11
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Estimating female malaria mosquito age by quantifying Y-linked genes in stored male spermatozoa. Sci Rep 2022; 12:10570. [PMID: 35732703 PMCID: PMC9217924 DOI: 10.1038/s41598-022-15021-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/16/2022] [Indexed: 11/19/2022] Open
Abstract
Vector control strategies are among the most effective measures to combat mosquito-borne diseases, such as malaria. These strategies work by altering the mosquito age structure through increased mortality of the older female mosquitoes that transmit pathogens. However, methods to monitor changes to mosquito age structure are currently inadequate for programmatic implementation. Female mosquitoes generally mate a single time soon after emergence and draw down spermatozoa reserves with each oviposition cycle. Here, we demonstrate that measuring spermatozoa quantity in female Anopheles mosquitoes is an effective approach to assess mosquito age. Using multiplexed qPCR targeted at male spermatozoa, we show that Y-linked genes in female mosquitoes are exclusively found in the spermatheca, the organ that houses spermatozoa, and the quantity of these gene sequences significantly declines with age. The method can accurately identify mosquitoes more than 10 days old and thus old enough to potentially transmit pathogens harbored in the salivary glands during blood feeding. Furthermore, mosquito populations that differ by 10% in daily survivorship have a high likelihood of being distinguished using modest sample sizes, making this approach scalable for assessing the efficacy of vector intervention control programs.
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Abstract
Insects have evolved highly diverse genetic sex-determination mechanisms and a relatively balanced male to female sex ratio is generally expected. However, selection may shift the optimal sex ratio while meiotic drive and endosymbiont manipulation can result in sex ratio distortion (SRD). Recent advances in sex chromosome genomics and CRISPR/Cas9-mediated genome editing brought significant insights into the molecular regulators of sex determination in an increasing number of insects and provided new ways to engineer SRD. We review these advances and discuss both naturally occurring and engineered SRD in the context of the Anthropocene. We emphasize SRD-mediated biological control of insects to help improve One Health, sustain agriculture, and conserve endangered species.
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Affiliation(s)
- Austin Compton
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
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13
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Chang CH, Gregory LE, Gordon KE, Meiklejohn CD, Larracuente AM. Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes. eLife 2022; 11:e75795. [PMID: 34989337 PMCID: PMC8794474 DOI: 10.7554/elife.75795] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/18/2021] [Indexed: 02/06/2023] Open
Abstract
Y chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposons, and satellite DNA. Sexual antagonism and a loss of recombination play major roles in the degeneration of young Y chromosomes. However, the processes shaping the evolution of mature, already degenerated Y chromosomes are less well-understood. Because Y chromosomes evolve rapidly, comparisons between closely related species are particularly useful. We generated de novo long-read assemblies complemented with cytological validation to reveal Y chromosome organization in three closely related species of the Drosophila simulans complex, which diverged only 250,000 years ago and share >98% sequence identity. We find these Y chromosomes are divergent in their organization and repetitive DNA composition and discover new Y-linked gene families whose evolution is driven by both positive selection and gene conversion. These Y chromosomes are also enriched for large deletions, suggesting that the repair of double-strand breaks on Y chromosomes may be biased toward microhomology-mediated end joining over canonical non-homologous end-joining. We propose that this repair mechanism contributes to the convergent evolution of Y chromosome organization across organisms.
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Affiliation(s)
- Ching-Ho Chang
- Department of Biology, University of RochesterRochesterUnited States
| | - Lauren E Gregory
- Department of Biology, University of RochesterRochesterUnited States
| | - Kathleen E Gordon
- School of Biological Sciences, University of Nebraska-LincolnLincolnUnited States
| | - Colin D Meiklejohn
- School of Biological Sciences, University of Nebraska-LincolnLincolnUnited States
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14
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Alcalay Y, Fuchs S, Galizi R, Bernardini F, Haghighat-Khah RE, Rusch DB, Adrion JR, Hahn MW, Tortosa P, Rotenberry R, Papathanos PA. The Potential for a Released Autosomal X-Shredder Becoming a Driving-Y Chromosome and Invasively Suppressing Wild Populations of Malaria Mosquitoes. Front Bioeng Biotechnol 2021; 9:752253. [PMID: 34957064 PMCID: PMC8698249 DOI: 10.3389/fbioe.2021.752253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/15/2021] [Indexed: 11/16/2022] Open
Abstract
Sex-ratio distorters based on X-chromosome shredding are more efficient than sterile male releases for population suppression. X-shredding is a form of sex distortion that skews spermatogenesis of XY males towards the preferential transmission of Y-bearing gametes, resulting in a higher fraction of sons than daughters. Strains harboring X-shredders on autosomes were first developed in the malaria mosquito Anopheles gambiae, resulting in strong sex-ratio distortion. Since autosomal X-shredders are transmitted in a Mendelian fashion and can be selected against, their frequency in the population declines once releases are halted. However, unintended transfer of X-shredders to the Y-chromosome could produce an invasive meiotic drive element, that benefits from its biased transmission to the predominant male-biased offspring and its effective shielding from female negative selection. Indeed, linkage to the Y-chromosome of an active X-shredder instigated the development of the nuclease-based X-shredding system. Here, we analyze mechanisms whereby an autosomal X-shredder could become unintentionally Y-linked after release by evaluating the stability of an established X-shredder strain that is being considered for release, exploring its potential for remobilization in laboratory and wild-type genomes of An. gambiae and provide data regarding expression on the mosquito Y-chromosome. Our data suggest that an invasive X-shredder resulting from a post-release movement of such autosomal transgenes onto the Y-chromosome is unlikely.
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Affiliation(s)
- Yehonatan Alcalay
- Department of Entomology, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Roberto Galizi
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, United Kingdom
| | - Federica Bernardini
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Douglas B Rusch
- Center for Genomics and Bioinformatics, Indiana University, Bloomington, IN, United States
| | - Jeffrey R Adrion
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Matthew W Hahn
- Department of Biology, Indiana University, Bloomington, IN, United States.,Department of Computer Science, Indiana University, Bloomington, IN, United States
| | - Pablo Tortosa
- Unité Mixte de Recherche Processus Infectieux en Milieu Insulaire Tropical (UMR PIMIT), Université de La Réunion, INSERM 1187, CNRS 9192, IRD 249, Plateforme de Recherche CYROI, Saint Denis, France
| | - Rachel Rotenberry
- Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Philippos Aris Papathanos
- Department of Entomology, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
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Gamez S, Chaverra-Rodriguez D, Buchman A, Kandul NP, Mendez-Sanchez SC, Bennett JB, Sánchez C HM, Yang T, Antoshechkin I, Duque JE, Papathanos PA, Marshall JM, Akbari OS. Exploiting a Y chromosome-linked Cas9 for sex selection and gene drive. Nat Commun 2021; 12:7202. [PMID: 34893590 PMCID: PMC8664916 DOI: 10.1038/s41467-021-27333-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/03/2021] [Indexed: 02/06/2023] Open
Abstract
CRISPR-based genetic engineering tools aimed to bias sex ratios, or drive effector genes into animal populations, often integrate the transgenes into autosomal chromosomes. However, in species with heterogametic sex chromsomes (e.g. XY, ZW), sex linkage of endonucleases could be beneficial to drive the expression in a sex-specific manner to produce genetic sexing systems, sex ratio distorters, or even sex-specific gene drives, for example. To explore this possibility, here we develop a transgenic line of Drosophila melanogaster expressing Cas9 from the Y chromosome. We functionally characterize the utility of this strain for both sex selection and gene drive finding it to be quite effective. To explore its utility for population control, we built mathematical models illustrating its dynamics as compared to other state-of-the-art systems designed for both population modification and suppression. Taken together, our results contribute to the development of current CRISPR genetic control tools and demonstrate the utility of using sex-linked Cas9 strains for genetic control of animals.
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Affiliation(s)
- Stephanie Gamez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
- Agragene Inc., San Diego, CA, 92121, USA
| | - Duverney Chaverra-Rodriguez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Anna Buchman
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
- Verily Life Sciences, South San Francisco, CA, 94080, USA
| | - Nikolay P Kandul
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Stelia C Mendez-Sanchez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
- Group for Research in Biochemistry and Microbiology (Grupo de Investigación en Bioquímica Y Microbiología-GIBIM), School of Chemistry, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Jared B Bennett
- Biophysics Graduate Group, University of California, Berkeley, CA, 94720, USA
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA, 94720, USA
| | - Héctor M Sánchez C
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA, 94720, USA
| | - Ting Yang
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering (BBE), California Institute of Technology, Pasadena, CA, 91125, USA
| | - Jonny E Duque
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA
- Centro de Investigaciones en Enfermedades Tropicales - CINTROP, Facultad de Salud, Escuela de Medicina, Departamento de Ciencias Básicas, Universidad Industrial de Santander, Piedecuesta, Santander, Colombia
| | - Philippos A Papathanos
- Department of Entomology, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - John M Marshall
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA, 94720, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA
| | - Omar S Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA.
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Zhuo JC, Zhang HH, Hu QL, Zhang JL, Lu JB, Li HJ, Xie YC, Wang WW, Zhang Y, Wang HQ, Huang HJ, Lu G, Chen JP, Li JM, Tu ZJ, Zhang CX. A feminizing switch in a hemimetabolous insect. SCIENCE ADVANCES 2021; 7:eabf9237. [PMID: 34826246 PMCID: PMC8626073 DOI: 10.1126/sciadv.abf9237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
The mechanism of sex determination remains poorly understood in hemimetabolous insects. Here, in the brown planthopper (BPH), Nilaparvata lugens, a hemipteran rice pest, we identified a feminizing switch or a female determiner (Nlfmd) that encodes a serine/arginine-rich protein. Knockdown of Nlfmd in female nymphs resulted in masculinization of both the somatic morphology and doublesex splicing. The female-specific isoform of Nlfmd, Nlfmd-F, is maternally deposited and zygotically transcribed. Depletion of Nlfmd by maternal RNAi or CRISPR-Cas9 resulted in female-specific embryonic lethality. Knockdown of an hnRNP40 family gene named female determiner 2 (Nlfmd2) also conferred masculinization. In vitro experiments showed that an Nlfmd2 isoform, NlFMD2340, bound the RAAGAA repeat motif in the Nldsx pre-mRNA and formed a protein complex with NlFMD-F to modulate Nldsx splicing, suggesting that NlFMD2 may function as an RNA binding partner of the feminizing switch NlFMD. Our results provide novel insights into the diverse mechanisms of insect sex determination.
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Affiliation(s)
- Ji-Chong Zhuo
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Hou-Hong Zhang
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Qing-Ling Hu
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Jin-Li Zhang
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Jia-Bao Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Han-Jing Li
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Yu-Cheng Xie
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
| | - Wei-Wei Wang
- Institute of Biochemistry, Zhejiang University, Hangzhou 310058, China
| | - Yan Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Hai-Qiang Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Hai-Jian Huang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Gang Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Jian-Ping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Jun-Min Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Zhi-Jian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
| | - Chuan-Xi Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
- Institute of Insect Science, Zhejiang University, Hangzhou 310058, China
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17
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Identification and Characterization of the Masculinizing Function of the Helicoverpa armigera Masc Gene. Int J Mol Sci 2021; 22:ijms22168650. [PMID: 34445352 PMCID: PMC8395511 DOI: 10.3390/ijms22168650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
The Masculinizer (Masc) gene has been known to control sex development and dosage compensation in lepidopterans. However, it remains unclear whether its ortholog exists and plays the same roles in distantly related lepidopterans such as Helicoverpa armigera. To address this question, we cloned Masc from H. armigera (HaMasc), which contains all essential functional domains of BmMasc, albeit with less than 30% amino acid sequence identity with BmMasc. Genomic PCR and qPCR analyses showed that HaMasc is a Z chromosome-linked gene since its genomic content in males (ZZ) was two times greater than that in females (ZW). RT-PCR and RT-qPCR analyses revealed that HaMasc expression was sex- and stage-biased, with significantly more transcripts in males and eggs than in females and other stages. Transfection of a mixture of three siRNAs of HaMasc into a male embryonic cell line of H. armigera led to the appearance of female-specific mRNA splicing isoforms of H. armigeradoublesex (Hadsx), a downstream target gene of HaMasc in the H. armigera sex determination pathway. The knockdown of HaMasc, starting from the third instar larvae resulted in a shift of Hadsx splicing from male to female isoforms, smaller male pupa and testes, fewer but larger/longer spermatocytes and sperm bundles, delayed pupation and internal fusion of the testes and follicles. These data demonstrate that HaMasc functions as a masculinizing gene in the H. armigera sex-determination cascade.
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18
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Extreme Y chromosome polymorphism corresponds to five male reproductive morphs of a freshwater fish. Nat Ecol Evol 2021; 5:939-948. [PMID: 33958755 DOI: 10.1038/s41559-021-01452-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/23/2021] [Indexed: 02/02/2023]
Abstract
Loss of recombination between sex chromosomes often depletes Y chromosomes of functional content and genetic variation, which might limit their potential to generate adaptive diversity. Males of the freshwater fish Poecilia parae occur as one of five discrete morphs, all of which shoal together in natural populations where morph frequency has been stable for over 50 years. Each morph uses a different complex reproductive strategy and morphs differ dramatically in colour, body size and mating behaviour. Morph phenotype is passed perfectly from father to son, indicating there are five Y haplotypes segregating in the species, which encode the complex male morph characteristics. Here, we examine Y diversity in natural populations of P. parae. Using linked-read sequencing on multiple P. parae females and males of all five morphs, we find that the genetic architecture of the male morphs evolved on the Y chromosome after recombination suppression had occurred with the X. Comparing Y chromosomes between each of the morphs, we show that, although the Ys of the three minor morphs that differ in colour are highly similar, there are substantial amounts of unique genetic material and divergence between the Ys of the three major morphs that differ in reproductive strategy, body size and mating behaviour. Altogether, our results suggest that the Y chromosome is able to overcome the constraints of recombination loss to generate extreme diversity, resulting in five discrete Y chromosomes that control complex reproductive strategies.
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Xiao C, Li J, Xie T, Chen J, Zhang S, Elaksher SH, Jiang F, Jiang Y, Zhang L, Zhang W, Xiang Y, Wu Z, Zhao S, Du X. The assembly of caprine Y chromosome sequence reveals a unique paternal phylogenetic pattern and improves our understanding of the origin of domestic goat. Ecol Evol 2021; 11:7779-7795. [PMID: 34188851 PMCID: PMC8216945 DOI: 10.1002/ece3.7611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 03/30/2021] [Accepted: 04/06/2021] [Indexed: 02/05/2023] Open
Abstract
The mammalian Y chromosome offers a unique perspective on the male reproduction and paternal evolutionary histories. However, further understanding of the Y chromosome biology for most mammals is hindered by the lack of a Y chromosome assembly. This study presents an integrated in silico strategy for identifying and assembling the goat Y-linked scaffolds using existing data. A total of 11.5 Mb Y-linked sequences were clustered into 33 scaffolds, and 187 protein-coding genes were annotated. We also identified high abundance of repetitive elements. A 5.84 Mb subset was further ordered into an assembly with the evidence from the goat radiation hybrid map (RH map). The existing whole-genome resequencing data of 96 goats (worldwide distribution) were utilized to exploit the paternal relationships among bezoars and domestic goats. Goat paternal lineages were clearly divided into two clades (Y1 and Y2), predating the goat domestication. Demographic history analyses indicated that maternal lineages experienced a bottleneck effect around 2,000 YBP (years before present), after which goats belonging to the A haplogroup spread worldwide from the Near East. As opposed to this, paternal lineages experienced a population decline around the 10,000 YBP. The evidence from the Y chromosome suggests that male goats were not affected by the A haplogroup worldwide transmission, which implies sexually unbalanced contribution to the goat trade and population expansion in post-Neolithic period.
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Affiliation(s)
- Changyi Xiao
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
| | - Jingjin Li
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
| | - Tanghui Xie
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
| | - Jianhai Chen
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
- Institutes for Systems GeneticsFrontiers Science Center for Disease‐related Molecular NetworkWest China HospitalSichuan UniversityChengduChina
| | - Sijia Zhang
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
| | - Salma Hassan Elaksher
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
- Genetics and Genetic Engineering DepartmentFaculty of AgricultureBenha UniversityMoshtohorEgypt
| | - Fan Jiang
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
| | - Yaoxin Jiang
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
| | - Lu Zhang
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
| | - Wei Zhang
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
| | - Yue Xiang
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
| | - Zhenyang Wu
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
- College of Agroforestry Engineering and PlanningTongren UniversityTongrenChina
| | - Shuhong Zhao
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
| | - Xiaoyong Du
- College of InformaticsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Agricultural Animal Genetics, Breeding and ReproductionMinistry of EducationCollege of Animal Science and Veterinary MedicineHuazhong Agricultural UniversityWuhanChina
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20
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Zamyatin A, Avdeyev P, Liang J, Sharma A, Chen C, Lukyanchikova V, Alexeev N, Tu Z, Alekseyev MA, Sharakhov IV. Chromosome-level genome assemblies of the malaria vectors Anopheles coluzzii and Anopheles arabiensis. Gigascience 2021; 10:giab017. [PMID: 33718948 PMCID: PMC7957348 DOI: 10.1093/gigascience/giab017] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/01/2021] [Accepted: 01/23/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Anopheles coluzzii and Anopheles arabiensis belong to the Anopheles gambiae complex and are among the major malaria vectors in sub-Saharan Africa. However, chromosome-level reference genome assemblies are still lacking for these medically important mosquito species. FINDINGS In this study, we produced de novo chromosome-level genome assemblies for A. coluzzii and A. arabiensis using the long-read Oxford Nanopore sequencing technology and the Hi-C scaffolding approach. We obtained 273.4 and 256.8 Mb of the total assemblies for A. coluzzii and A. arabiensis, respectively. Each assembly consists of 3 chromosome-scale scaffolds (X, 2, 3), complete mitochondrion, and unordered contigs identified as autosomal pericentromeric DNA, X pericentromeric DNA, and Y sequences. Comparison of these assemblies with the existing assemblies for these species demonstrated that we obtained improved reference-quality genomes. The new assemblies allowed us to identify genomic coordinates for the breakpoint regions of fixed and polymorphic chromosomal inversions in A. coluzzii and A. arabiensis. CONCLUSION The new chromosome-level assemblies will facilitate functional and population genomic studies in A. coluzzii and A. arabiensis. The presented assembly pipeline will accelerate progress toward creating high-quality genome references for other disease vectors.
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Affiliation(s)
- Anton Zamyatin
- Computer Technologies Laboratory, ITMO University, Kronverkskiy Prospekt 49-A, Saint Petersburg 197101, Russia
| | - Pavel Avdeyev
- Department of Mathematics, The George Washington University, 801 22nd Street NW, Washington, DC 20052, USA
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, 800 22nd Street NW, Washington, DC 20052, USA
| | - Jiangtao Liang
- Department of Entomology, Virginia Polytechnic Institute and State University, 170 Drillfield Drive, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
| | - Atashi Sharma
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Chujia Chen
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Varvara Lukyanchikova
- Department of Entomology, Virginia Polytechnic Institute and State University, 170 Drillfield Drive, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
- Institute of Cytology and Genetics the Siberian Division of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, Novosibirsk 630090, Russia
| | - Nikita Alexeev
- Computer Technologies Laboratory, ITMO University, Kronverkskiy Prospekt 49-A, Saint Petersburg 197101, Russia
| | - Zhijian Tu
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Max A Alekseyev
- Department of Mathematics, The George Washington University, 801 22nd Street NW, Washington, DC 20052, USA
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, 800 22nd Street NW, Washington, DC 20052, USA
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, 170 Drillfield Drive, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA 24061, USA
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21
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Profile of Nora J. Besansky. Proc Natl Acad Sci U S A 2021; 118:2101734118. [PMID: 33627410 DOI: 10.1073/pnas.2101734118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Navarro-Escalante L, Hernandez-Hernandez EM, Nuñez J, Acevedo FE, Berrio A, Constantino LM, Padilla-Hurtado BE, Molina D, Gongora C, Acuña R, Stuart J, Benavides P. A coffee berry borer (Hypothenemus hampei) genome assembly reveals a reduced chemosensory receptor gene repertoire and male-specific genome sequences. Sci Rep 2021; 11:4900. [PMID: 33649370 PMCID: PMC7921381 DOI: 10.1038/s41598-021-84068-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 01/12/2021] [Indexed: 01/31/2023] Open
Abstract
Coffee berry borer-CBB (Hypothenemus hampei) is a globally important economic pest of coffee (Coffea spp.). Despite current insect control methods for managing CBB, development of future control strategies requires a better understanding of its biology and interaction with its host plant. Towards this objective, we performed de novo CBB genome and transcriptome sequencing, improved CBB genome assembly and predicted 18,765 protein-encoding genes. Using genome and transcriptome data, we annotated the genes associated with chemosensation and found a reduced gene repertoire composed by 67 odorant receptors (ORs), 62 gustatory receptors (GRs), 33 ionotropic receptors (IRs) and 29 odorant-binding proteins (OBPs). In silico transcript abundance analysis of these chemosensory genes revealed expression enrichment in CBB adults compared with larva. Detection of differentially expressed chemosensory genes between males and females is likely associated with differences in host-finding behavior between sexes. Additionally, we discovered male-specific genome content and identified candidate male-specific expressed genes on these scaffolds, suggesting that a Y-like chromosome may be involved in the CBB's functional haplodiploid mechanism of sex determination.
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Affiliation(s)
| | | | - Jonathan Nuñez
- Manaaki Whenua-Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand
| | - Flor E Acevedo
- Department of Entomology, Pennsylvania State University, University Park, PA, USA
| | | | | | - Beatriz E Padilla-Hurtado
- Instituto de Investigación en Microbiología Y Biotecnología Agroindustrial, Universidad Católica de Manizales, Manizales, Colombia
| | - Diana Molina
- National Coffee Research Center-CENICAFE, Manizales, Colombia
| | | | - Ricardo Acuña
- National Coffee Research Center-CENICAFE, Manizales, Colombia
| | - Jeff Stuart
- Department of Entomology, Purdue University, West Lafayette, USA
| | - Pablo Benavides
- National Coffee Research Center-CENICAFE, Manizales, Colombia
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23
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Chakraborty M, Ramaiah A, Adolfi A, Halas P, Kaduskar B, Ngo LT, Jayaprasad S, Paul K, Whadgar S, Srinivasan S, Subramani S, Bier E, James AA, Emerson JJ. Hidden genomic features of an invasive malaria vector, Anopheles stephensi, revealed by a chromosome-level genome assembly. BMC Biol 2021; 19:28. [PMID: 33568145 PMCID: PMC7876825 DOI: 10.1186/s12915-021-00963-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/19/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The mosquito Anopheles stephensi is a vector of urban malaria in Asia that recently invaded Africa. Studying the genetic basis of vectorial capacity and engineering genetic interventions are both impeded by limitations of a vector's genome assembly. The existing assemblies of An. stephensi are draft-quality and contain thousands of sequence gaps, potentially missing genetic elements important for its biology and evolution. RESULTS To access previously intractable genomic regions, we generated a reference-grade genome assembly and full transcript annotations that achieve a new standard for reference genomes of disease vectors. Here, we report novel species-specific transposable element (TE) families and insertions in functional genetic elements, demonstrating the widespread role of TEs in genome evolution and phenotypic variation. We discovered 29 previously hidden members of insecticide resistance genes, uncovering new candidate genetic elements for the widespread insecticide resistance observed in An. stephensi. We identified 2.4 Mb of the Y chromosome and seven new male-linked gene candidates, representing the most extensive coverage of the Y chromosome in any mosquito. By tracking full-length mRNA for > 15 days following blood feeding, we discover distinct roles of previously uncharacterized genes in blood metabolism and female reproduction. The Y-linked heterochromatin landscape reveals extensive accumulation of long-terminal repeat retrotransposons throughout the evolution and degeneration of this chromosome. Finally, we identify a novel Y-linked putative transcription factor that is expressed constitutively throughout male development and adulthood, suggesting an important role. CONCLUSION Collectively, these results and resources underscore the significance of previously hidden genomic elements in the biology of malaria mosquitoes and will accelerate the development of genetic control strategies of malaria transmission.
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Affiliation(s)
- Mahul Chakraborty
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697, USA
| | - Arunachalam Ramaiah
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697, USA
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093-0335, USA
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India
| | - Adriana Adolfi
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, 92697, USA
| | - Paige Halas
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, 92697, USA
| | - Bhagyashree Kaduskar
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093-0335, USA
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India
| | - Luna Thanh Ngo
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697, USA
| | - Suvratha Jayaprasad
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, KA, 560100, India
| | - Kiran Paul
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, KA, 560100, India
| | - Saurabh Whadgar
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, KA, 560100, India
| | - Subhashini Srinivasan
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, KA, 560100, India
| | - Suresh Subramani
- Tata Institute for Genetics and Society, Center at inStem, Bangalore, Karnataka, 560065, India
- Section of Molecular Biology, University of California, San Diego, La Jolla, CA, 92093-0322, USA
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093-0335, USA
| | - Ethan Bier
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093-0335, USA
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093-0335, USA
| | - Anthony A James
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, 92697, USA
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA, 92093-0335, USA
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697, USA
| | - J J Emerson
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697, USA.
- Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA.
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24
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Chen XI, Mei Y, Chen M, Jing D, He Y, Liu F, He K, Li F. InSexBase: an annotated genomic resource of sex chromosomes and sex-biased genes in insects. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2021; 2021:6122465. [PMID: 33507270 PMCID: PMC7904046 DOI: 10.1093/database/baab001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/09/2020] [Accepted: 01/06/2021] [Indexed: 11/13/2022]
Abstract
Sex determination and the regulation of sexual dimorphism are among the most fascinating topics in modern biology. As the most species-rich group of sexually reproducing organisms on Earth, insects have multiple sex determination systems. Though sex chromosomes and sex-biased genes are well-studied in dozens of insects, their gene sequences are scattered in various databases. Moreover, a shortage of annotation hinders the deep mining of these data. Here, we collected the chromosome-level sex chromosome data of 49 insect species, including 34 X chromosomes, 15 Z chromosomes, 5 W chromosomes and 2 Y chromosomes. We also obtained Y-linked contigs of four insects species—Anopheles gambiae, Drosophila innubila, Drosophila yakuba and Tribolium castaneum. The unannotated chromosome-level sex chromosomes were annotated using a standard pipeline, yielding a total of 123 030 protein-coding genes, 2 159 427 repeat sequences, 894 miRNAs, 1574 rRNAs, 5105 tRNAs, 395 snoRNAs (small nucleolar RNA), 54 snRNAs (small nuclear RNA) and 5959 other ncRNAs (non-coding RNA). In addition, 36 781 sex-biased genes were identified by analyzing 62 RNA-seq (RNA sequencing) datasets. Together with 5707 sex-biased genes from the Drosophila genus collected from the Sex-Associated Gene Database, we obtained a total of 42 488 sex-biased genes from 13 insect species. All these data were deposited into InSexBase, a new user-friendly database of insect sex chromosomes and sex-biased genes. Database URL:http://www.insect-genome.com/Sexdb/.
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Affiliation(s)
- X I Chen
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Yang Mei
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Mengyao Chen
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Dong Jing
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Yumin He
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Feiling Liu
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Kang He
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
| | - Fei Li
- Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects & Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Yuhangtang Rd 866, Xihu District, Hanzghou, 310058, China
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25
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Kranjc N, Crisanti A, Nolan T, Bernardini F. Anopheles gambiae Genome Conservation as a Resource for Rational Gene Drive Target Site Selection. INSECTS 2021; 12:97. [PMID: 33498790 PMCID: PMC7911984 DOI: 10.3390/insects12020097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/15/2022]
Abstract
The increase in molecular tools for the genetic engineering of insect pests and disease vectors, such as Anopheles mosquitoes that transmit malaria, has led to an unprecedented investigation of the genomic landscape of these organisms. The understanding of genome variability in wild mosquito populations is of primary importance for vector control strategies. This is particularly the case for gene drive systems, which look to introduce genetic traits into a population by targeting specific genomic regions. Gene drive targets with functional or structural constraints are highly desirable as they are less likely to tolerate mutations that prevent targeting by the gene drive and consequent failure of the technology. In this study we describe a bioinformatic pipeline that allows the analysis of whole genome data for the identification of highly conserved regions that can point at potential functional or structural constraints. The analysis was conducted across the genomes of 22 insect species separated by more than hundred million years of evolution and includes the observed genomic variation within field caught samples of Anopheles gambiae and Anopheles coluzzii, the two most dominant malaria vectors. This study offers insight into the level of conservation at a genome-wide scale as well as at per base-pair resolution. The results of this analysis are gathered in a data storage system that allows for flexible extraction and bioinformatic manipulation. Furthermore, it represents a valuable resource that could provide insight into population structure and dynamics of the species in the complex and benefit the development and implementation of genetic strategies to tackle malaria.
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Affiliation(s)
- Nace Kranjc
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
| | - Tony Nolan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Federica Bernardini
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
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26
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Sproul JS, Barton LM, Maddison DR. Repetitive DNA Profiles Reveal Evidence of Rapid Genome Evolution and Reflect Species Boundaries in Ground Beetles. Syst Biol 2021; 69:1137-1148. [PMID: 32267949 DOI: 10.1093/sysbio/syaa030] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 03/16/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Genome architecture is a complex, multidimensional property of an organism defined by the content and spatial organization of the genome's component parts. Comparative study of entire genome architecture in model organisms is shedding light on mechanisms underlying genome regulation, evolution, and diversification, but such studies require costly analytical approaches which make extensive comparative study impractical for most groups. However, lower-cost methods that measure a single architectural component (e.g., distribution of one class of repeats) have potential as a new data source for evolutionary studies insofar as that measure correlates with more complex biological phenomena, and for which it could serve as part of an explanatory framework. We investigated copy number variation (CNV) profiles in ribosomal DNA (rDNA) as a simple measure reflecting the distribution of rDNA subcomponents across the genome. We find that signatures present in rDNA CNV profiles strongly correlate with species boundaries in the breve species group of Bembidion, and vary across broader taxonomic sampling in Bembidion subgenus Plataphus. Profiles of several species show evidence of re-patterning of rDNA-like sequences throughout the genome, revealing evidence of rapid genome evolution (including among sister pairs) not evident from analysis of traditional data sources such as multigene data sets. Major re-patterning of rDNA-like sequences has occurred frequently within the evolutionary history of Plataphus. We confirm that CNV profiles represent an aspect of genomic architecture (i.e., the linear distribution of rDNA components across the genome) via fluorescence in-situ hybridization. In at least one species, novel rDNA-like elements are spread throughout all chromosomes. We discuss the potential of copy number profiles of rDNA, or other repeats, as a low-cost tool for incorporating signal of genomic architecture variation in studies of species delimitation and genome evolution. [Bembidion; Carabidae; copy number variation profiles; rapid genome evolution; ribosomal DNA; species delimitation.].
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Affiliation(s)
- John S Sproul
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA.,Department of Biology, University of Rochester, 402 Hutchison Hall, PO Box 270211, Rochester, NY 14627, USA
| | - Lindsey M Barton
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA
| | - David R Maddison
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA
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27
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Tennessen JA, Ingham VA, Toé KH, Guelbéogo WM, Sagnon N, Kuzma R, Ranson H, Neafsey DE. A population genomic unveiling of a new cryptic mosquito taxon within the malaria-transmitting Anopheles gambiae complex. Mol Ecol 2020; 30:775-790. [PMID: 33253481 DOI: 10.1111/mec.15756] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 11/24/2020] [Indexed: 02/05/2023]
Abstract
The Anopheles gambiae complex consists of multiple morphologically indistinguishable mosquito species including the most important vectors of the malaria parasite Plasmodium falciparum in sub-Saharan Africa. Nine cryptic species have been described so far within the complex. The ecological, immunological and reproductive differences among these species will critically impact population responses to disease control strategies and environmental changes. Here, we examine whole-genome sequencing data from a longitudinal study of putative A. coluzzii in western Burkina Faso. Surprisingly, many specimens are genetically divergent from A. coluzzii and all other Anopheles species and represent a new taxon, here designated Anopheles TENGRELA (AT). Population genetic analysis suggests that the cryptic GOUNDRY subgroup, previously collected as larvae in central Burkina Faso, represents an admixed population descended from both A. coluzzii and AT. AT harbours low nucleotide diversity except for the 2La inversion polymorphism which is maintained by overdominance. It shows numerous fixed differences with A. coluzzii concentrated in several regions reflecting selective sweeps, but the two taxa are identical at standard diagnostic loci used for taxon identification, and thus, AT may often go unnoticed. We present an amplicon-based genotyping assay for identifying AT which could be usefully applied to numerous existing samples. Misidentified cryptic taxa could seriously confound ongoing studies of Anopheles ecology and evolution in western Africa, including phenotypic and genotypic surveys of insecticide resistance. Reproductive barriers between cryptic species may also complicate novel vector control efforts, for example gene drives, and hinder predictions about evolutionary dynamics of Anopheles and Plasmodium.
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Affiliation(s)
- Jacob A Tennessen
- Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Broad Institute, Cambridge, MA, USA
| | | | - Kobié Hyacinthe Toé
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - N'Falé Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Rebecca Kuzma
- Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Broad Institute, Cambridge, MA, USA
| | - Hilary Ranson
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Daniel E Neafsey
- Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Broad Institute, Cambridge, MA, USA
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28
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Ye X, Xiong S, Teng Z, Yang Y, Wang J, Yu K, Wu H, Mei Y, Yan Z, Cheng S, Yin C, Wang F, Yao H, Fang Q, Song Q, Werren JH, Ye G, Li F. Amino acid synthesis loss in parasitoid wasps and other hymenopterans. eLife 2020; 9:e59795. [PMID: 33074103 PMCID: PMC7593089 DOI: 10.7554/elife.59795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/17/2020] [Indexed: 11/17/2022] Open
Abstract
Insects utilize diverse food resources which can affect the evolution of their genomic repertoire, including leading to gene losses in different nutrient pathways. Here, we investigate gene loss in amino acid synthesis pathways, with special attention to hymenopterans and parasitoid wasps. Using comparative genomics, we find that synthesis capability for tryptophan, phenylalanine, tyrosine, and histidine was lost in holometabolous insects prior to hymenopteran divergence, while valine, leucine, and isoleucine were lost in the common ancestor of Hymenoptera. Subsequently, multiple loss events of lysine synthesis occurred independently in the Parasitoida and Aculeata. Experiments in the parasitoid Cotesia chilonis confirm that it has lost the ability to synthesize eight amino acids. Our findings provide insights into amino acid synthesis evolution, and specifically can be used to inform the design of parasitoid artificial diets for pest control.
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Affiliation(s)
- Xinhai Ye
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
- Department of Biology, University of RochesterRochesterUnited States
| | - Shijiao Xiong
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Ziwen Teng
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Yi Yang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Jiale Wang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Kaili Yu
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Huizi Wu
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Yang Mei
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Zhichao Yan
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Sammy Cheng
- Department of Biology, University of RochesterRochesterUnited States
| | - Chuanlin Yin
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Fang Wang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Hongwei Yao
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Qi Fang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Qisheng Song
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, University of MissouriColumbiaUnited States
| | - John H Werren
- Department of Biology, University of RochesterRochesterUnited States
| | - Gongyin Ye
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
| | - Fei Li
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang UniversityHangzhouChina
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29
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Haghighat-Khah RE, Sharma A, Wunderlich MR, Morselli G, Marston LA, Bamikole C, Hall A, Kranjc N, Taxiarchi C, Sharakhov I, Galizi R. Cellular mechanisms regulating synthetic sex ratio distortion in the Anopheles gambiae germline. Pathog Glob Health 2020; 114:370-378. [PMID: 33043870 PMCID: PMC7580827 DOI: 10.1080/20477724.2020.1803628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Genetic control strategies aimed to bias the sex of progenies towards males present a promising new paradigm to eliminate malaria-transmitting mosquitoes. A synthetic sex-ratio distortion (SD) system was successfully engineered in Anopheles gambiae by exploiting the meiotic activity of the I-PpoI endonuclease targeting ribosomal DNA (rDNA) repeats, exclusively located on the X chromosome. Males carrying the SD construct produce highly male-biased progenies without evident reduction in fertility. In this study, we investigated the fate of X and Y chromosomes in these SD males and found that ratios of mature X:Y-bearing sperm were comparable to wild-type insects, indicating absence of selection mechanisms during sperm maturation. We therefore tested the effect of meiotic cleavage of both X and Y chromosomes in a lab-generated SD strain carrying rDNA on both sex chromosomes, showing fertility comparable to wild-type and a reduced male-bias compared to SD males in which only the X is targeted. Exposure of Y-linked rDNA to I-PpoI cleavage for consecutive generations rapidly restored the male-bias to typical high frequencies, indicating a correlation between the number of cleavable targets in each sex chromosome and the sex-ratios found in the progeny. Altogether our results indicate that meiotic cleavage of rDNA repeats, located in the sex chromosomes of A. gambiae SD males, affects the competitiveness of mature sperm to fertilize the female oocyte, thereby generating sex-biased progenies. We also show that the presence of rDNA copies on the Y chromosome does not impair the effectiveness of engineered synthetic SD systems for the control of human malaria mosquitoes.
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Affiliation(s)
| | - Atashi Sharma
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | | | - Giulia Morselli
- Department of Life Sciences, Imperial College London, London, UK
| | | | | | - Ann Hall
- Department of Life Sciences, Imperial College London, London, UK
| | - Nace Kranjc
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Igor Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
- Department of Cytology and Genetics, Tomsk State University, Tomsk, Russian Federation
| | - Roberto Galizi
- Department of Life Sciences, Imperial College London, London, UK
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, UK
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30
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Peichel CL, McCann SR, Ross JA, Naftaly AFS, Urton JR, Cech JN, Grimwood J, Schmutz J, Myers RM, Kingsley DM, White MA. Assembly of the threespine stickleback Y chromosome reveals convergent signatures of sex chromosome evolution. Genome Biol 2020; 21:177. [PMID: 32684159 PMCID: PMC7368989 DOI: 10.1186/s13059-020-02097-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/08/2020] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Heteromorphic sex chromosomes have evolved repeatedly across diverse species. Suppression of recombination between X and Y chromosomes leads to degeneration of the Y chromosome. The progression of degeneration is not well understood, as complete sequence assemblies of heteromorphic Y chromosomes have only been generated across a handful of taxa with highly degenerate sex chromosomes. Here, we describe the assembly of the threespine stickleback (Gasterosteus aculeatus) Y chromosome, which is less than 26 million years old and at an intermediate stage of degeneration. Our previous work identified that the non-recombining region between the X and the Y spans approximately 17.5 Mb on the X chromosome. RESULTS We combine long-read sequencing with a Hi-C-based proximity guided assembly to generate a 15.87 Mb assembly of the Y chromosome. Our assembly is concordant with cytogenetic maps and Sanger sequences of over 90 Y chromosome BAC clones. We find three evolutionary strata on the Y chromosome, consistent with the three inversions identified by our previous cytogenetic analyses. The threespine stickleback Y shows convergence with more degenerate sex chromosomes in the retention of haploinsufficient genes and the accumulation of genes with testis-biased expression, many of which are recent duplicates. However, we find no evidence for large amplicons identified in other sex chromosome systems. We also report an excellent candidate for the master sex-determination gene: a translocated copy of Amh (Amhy). CONCLUSIONS Together, our work shows that the evolutionary forces shaping sex chromosomes can cause relatively rapid changes in the overall genetic architecture of Y chromosomes.
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Affiliation(s)
- Catherine L. Peichel
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
- Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
| | - Shaugnessy R. McCann
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
| | - Joseph A. Ross
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
- Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195 USA
| | | | - James R. Urton
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
- Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195 USA
| | - Jennifer N. Cech
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
- Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195 USA
| | - Jane Grimwood
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806 USA
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806 USA
| | - Richard M. Myers
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806 USA
| | - David M. Kingsley
- Department of Developmental Biology and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Michael A. White
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
- Department of Genetics, University of Georgia, Athens, GA 30602 USA
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Nix alone is sufficient to convert female Aedes aegypti into fertile males and myo-sex is needed for male flight. Proc Natl Acad Sci U S A 2020; 117:17702-17709. [PMID: 32661163 PMCID: PMC7395513 DOI: 10.1073/pnas.2001132117] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The presence of a dominant male-determining locus (M-locus) in one of a pair of autosomes establishes the male sex in the dengue fever mosquito Aedes aegypti. The Ae. aegypti M-locus contains 30 genes, including Nix, a previously reported male-determining factor. Here we show that the Nix transgene alone was sufficient to convert females into fertile males, which continued to produce sex-converted progeny. We also show that a second M-locus gene named myo-sex was needed for male flight. Nix-mediated sex conversion was 100% penetrant, heritable, and stable, indicating great potential for developing mosquito-control strategies to reduce vector populations by female-to-male conversion. This work also sheds lights into the molecular basis of the function of the M-locus. A dominant male-determining locus (M-locus) establishes the male sex (M/m) in the yellow fever mosquito, Aedes aegypti. Nix, a gene in the M-locus, was shown to be a male-determining factor (M factor) as somatic knockout of Nix led to feminized males (M/m) while transient expression of Nix resulted in partially masculinized females (m/m), with male reproductive organs but retained female antennae. It was not clear whether any of the other 29 genes in the 1.3-Mb M-locus are also needed for complete sex-conversion. Here, we report the generation of multiple transgenic lines that express Nix under the control of its own promoter. Genetic and molecular analyses of these lines provided insights unattainable from previous transient experiments. We show that the Nix transgene alone, in the absence of the M-locus, was sufficient to convert females into males with all male-specific sexually dimorphic features and male-like gene expression. The converted m/m males are flightless, unable to perform the nuptial flight required for mating. However, they were able to father sex-converted progeny when presented with cold-anesthetized wild-type females. We show that myo-sex, a myosin heavy-chain gene also in the M-locus, was required for male flight as knockout of myo-sex rendered wild-type males flightless. We also show that Nix-mediated female-to-male conversion was 100% penetrant and stable over many generations. Therefore, Nix has great potential for developing mosquito control strategies to reduce vector populations by female-to-male sex conversion, or to aid in a sterile insect technique that requires releasing only non-biting males.
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32
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Sharma A, Kinney NA, Timoshevskiy VA, Sharakhova MV, Sharakhov IV. Structural Variation of the X Chromosome Heterochromatin in the Anopheles gambiae Complex. Genes (Basel) 2020; 11:E327. [PMID: 32204543 PMCID: PMC7140835 DOI: 10.3390/genes11030327] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/31/2022] Open
Abstract
Heterochromatin is identified as a potential factor driving diversification of species. To understand the magnitude of heterochromatin variation within the Anopheles gambiae complex of malaria mosquitoes, we analyzed metaphase chromosomes in An. arabiensis, An. coluzzii, An. gambiae, An. merus, and An. quadriannulatus. Using fluorescence in situ hybridization (FISH) with ribosomal DNA (rDNA), a highly repetitive fraction of DNA, and heterochromatic Bacterial Artificial Chromosome (BAC) clones, we established the correspondence of pericentric heterochromatin between the metaphase and polytene X chromosomes of An. gambiae. We then developed chromosome idiograms and demonstrated that the X chromosomes exhibit qualitative differences in their pattern of heterochromatic bands and position of satellite DNA (satDNA) repeats among the sibling species with postzygotic isolation, An. arabiensis, An. merus, An. quadriannulatus, and An. coluzzii or An. gambiae. The identified differences in the size and structure of the X chromosome heterochromatin point to a possible role of repetitive DNA in speciation of mosquitoes. We found that An. coluzzii and An. gambiae, incipient species with prezygotic isolation, share variations in the relative positions of the satDNA repeats and the proximal heterochromatin band on the X chromosomes. This previously unknown genetic polymorphism in malaria mosquitoes may be caused by a differential amplification of DNA repeats or an inversion in the sex chromosome heterochromatin.
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Affiliation(s)
- Atashi Sharma
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
| | - Nicholas A. Kinney
- Genomics Bioinformatics and Computational Biology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA;
| | - Vladimir A. Timoshevskiy
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
| | - Maria V. Sharakhova
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
- Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 634050 Tomsk, Russia
| | - Igor V. Sharakhov
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
- Genomics Bioinformatics and Computational Biology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA;
- Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Cytology and Genetics, Tomsk State University, 634050 Tomsk, Russia
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33
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A fly model establishes distinct mechanisms for synthetic CRISPR/Cas9 sex distorters. PLoS Genet 2020; 16:e1008647. [PMID: 32168334 PMCID: PMC7108745 DOI: 10.1371/journal.pgen.1008647] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/31/2020] [Accepted: 02/03/2020] [Indexed: 01/24/2023] Open
Abstract
Synthetic sex distorters have recently been developed in the malaria mosquito, relying on endonucleases that target the X-chromosome during spermatogenesis. Although inspired by naturally-occurring traits, it has remained unclear how they function and, given their potential for genetic control, how portable this strategy is across species. We established Drosophila models for two distinct mechanisms for CRISPR/Cas9 sex-ratio distortion—“X-shredding” and “X-poisoning”—and dissected their target-site requirements and repair dynamics. X-shredding resulted in sex distortion when Cas9 endonuclease activity occurred during the meiotic stages of spermatogenesis but not when Cas9 was expressed from the stem cell stages onwards. Our results suggest that X-shredding is counteracted by the NHEJ DNA repair pathway and can operate on a single repeat cluster of non-essential sequences, although the targeting of a number of such repeats had no effect on the sex ratio. X-poisoning by contrast, i.e. targeting putative haplolethal genes on the X chromosome, induced a high bias towards males (>92%) when we directed Cas9 cleavage to the X-linked ribosomal target gene RpS6. In the case of X-poisoning sex distortion was coupled to a loss in reproductive output, although a dominant-negative effect appeared to drive the mechanism of female lethality. These model systems will guide the study and the application of sex distorters to medically or agriculturally important insect target species. Harmful insect populations can be eliminated for a lack of females if they are made to produce mostly male offspring. There are genes that occur naturally that make males produce mostly sons and, although we don’t know exactly how they work, this appears to coincide with damage to the X-chromosome during the production of sperm. Recently, we showed in a mosquito species that such sex-biasing genes could also be constructed artificially from first principles. To better understand if this works in other species too, we designed and built male-biasing genes of two types in the fruit fly and determined what is needed to for a shift towards males. We show how different ways of cutting the X-chromosome DNA at different times with CRISPR, results in distinct outcomes and started to ask what cellular processes are involved in this. These models will help us to design such genes for the control of insect species that transmit disease or threaten crops.
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34
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High-resolution transcriptional profiling of Anopheles gambiae spermatogenesis reveals mechanisms of sex chromosome regulation. Sci Rep 2019; 9:14841. [PMID: 31619757 PMCID: PMC6795909 DOI: 10.1038/s41598-019-51181-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022] Open
Abstract
Although of high priority for the development of genetic tools to control malaria-transmitting mosquitoes, only a few germline-specific regulatory regions have been characterised to date and the presence of global regulatory mechanisms, such as dosage compensation and meiotic sex chromosome inactivation (MSCI), are mostly assumed from transcriptomic analyses of reproductive tissues or whole gonads. In such studies, samples include a significant portion of somatic tissues inevitably complicating the reconstruction of a defined transcriptional map of gametogenesis. By exploiting recent advances in transgenic technologies and gene editing tools, combined with fluorescence-activated cell sorting and RNA sequencing, we have separated four distinct cell lineages from the Anopheles gambiae male gonads: premeiotic, meiotic (primary and secondary spermatocytes) and postmeiotic. By comparing the overall expression levels of X-linked and autosomal genes across the four populations, we revealed a striking transcriptional repression of the X chromosome coincident with the meiotic phase, classifiable as MSCI, and highlighted genes that may evade silencing. In addition, chromosome-wide median expression ratios of the premeiotic population confirmed the absence of dosage compensation in the male germline. Applying differential expression analysis, we highlighted genes and transcript isoforms enriched at specific timepoints and reconstructed the expression dynamics of the main biological processes regulating the key stages of sperm development and maturation. We generated the first transcriptomic atlas of A. gambiae spermatogenesis that will expand the available toolbox for the genetic engineering of vector control technologies. We also describe an innovative and multidimensional approach to isolate specific cell lineages that can be used for the targeted analysis of other A. gambiae organs or transferred to other medically relevant species and model organisms.
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35
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Zhu S, Emrich SJ, Chen DZ. Predicting Local Inversions Using Rectangle Clustering and Representative Rectangle Prediction. IEEE Trans Nanobioscience 2019; 18:316-323. [PMID: 31180865 PMCID: PMC6606370 DOI: 10.1109/tnb.2019.2915060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
As a specific type of structural variation, inversions are enjoying particular traction as a result of their established role in evolution. Using third-generation sequencing technology to predict inversions is growing in interest, but many such methods focus on improving sensitivity, giving rise to either too many false positives or very long running times. In this paper, we propose a new framework for inversion detection based on a combination of two novel theoretical models: rectangle clustering and representative rectangle prediction. This combination can automatically filter out false positive inversion predictions while retaining correct ones, leading to a method that has both high sensitivity and high positive prediction values (PPV). Further, this new framework can run very fast on available data. Our software can be freely obtained at https://github.com/UTbioinf/RigInv.
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36
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Thawornwattana Y, Dalquen D, Yang Z. Coalescent Analysis of Phylogenomic Data Confidently Resolves the Species Relationships in the Anopheles gambiae Species Complex. Mol Biol Evol 2019; 35:2512-2527. [PMID: 30102363 PMCID: PMC6188554 DOI: 10.1093/molbev/msy158] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Deep coalescence and introgression make it challenging to infer phylogenetic relationships among closely related species that arose through radiative speciation events. Despite numerous phylogenetic analyses and the availability of whole genomes, the phylogeny in the Anopheles gambiae species complex has not been confidently resolved. Here we extract over 80, 000 coding and noncoding short segments (called loci) from the genomes of six members of the species complex and use a Bayesian method under the multispecies coalescent model to infer the species tree, which takes into account genealogical heterogeneity across the genome and uncertainty in the gene trees. We obtained a robust estimate of the species tree from the distal region of the X chromosome: (A. merus, ((A. melas, (A. arabiensis, A. quadriannulatus)), (A. gambiae, A. coluzzii))), with A. merus to be the earliest branching species. This species tree agrees with the chromosome inversion phylogeny and provides a parsimonious interpretation of inversion and introgression events. Simulation informed by the real data suggest that the coalescent approach is reliable while the sliding-window analysis used in a previous phylogenomic study generates artifactual species trees. Likelihood ratio test of gene flow revealed strong evidence of autosomal introgression from A. arabiensis into A. gambiae (at the average rate of ∼0.2 migrants per generation), but not in the opposite direction, and introgression of the 3 L chromosomal region from A. merus into A. quadriannulatus. Our results highlight the importance of accommodating incomplete lineage sorting and introgression in phylogenomic analyses of species that arose through recent radiative speciation events.
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Affiliation(s)
- Yuttapong Thawornwattana
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom.,Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Daniel Dalquen
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Ziheng Yang
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom.,Radcliffe Institute for Advanced Studies, Harvard University, Cambridge, MA
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37
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Buchman A, Akbari OS. Site-specific transgenesis of the Drosophila melanogaster Y-chromosome using CRISPR/Cas9. INSECT MOLECULAR BIOLOGY 2019; 28:65-73. [PMID: 30079589 PMCID: PMC8459378 DOI: 10.1111/imb.12528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite the importance of Y-chromosomes in evolution and sex determination, their heterochromatic, repeat-rich nature makes them difficult to sequence (due, in part, to ambiguities in sequence alignment and assembly) and to genetically manipulate. Therefore, they generally remain poorly understood. For example, the Drosophila melanogaster Y-chromosome, one of the most extensively studied Y-chromosomes, is widely heterochromatic and composed mainly of highly repetitive sequences, with only a handful of expressed genes scattered throughout its length. Efforts to insert transgenes on this chromosome have thus far relied on either random insertion of transposons (sometimes harbouring 'landing sites' for subsequent integrations) with limited success or on chromosomal translocations, thereby limiting the types of Y-chromosome-related questions that could be explored. Here, we describe a versatile approach to site-specifically insert transgenes on the Y-chromosome in D. melanogaster via CRISPR/Cas9-mediated homology-directed repair. We demonstrate the ability to insert, and detect expression from, fluorescently marked transgenes at two specific locations on the Y-chromosome, and we utilize these marked Y-chromosomes to detect and quantify rare chromosomal nondisjunction effects. Finally, we discuss how this Y-docking technique could be adapted to other insects to aid in the development of genetic control technologies for the management of insect disease vectors and pests.
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Affiliation(s)
- Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
| | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA 92093, United States of America
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38
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Ruzzante L, Reijnders MJ, Waterhouse RM. Of Genes and Genomes: Mosquito Evolution and Diversity. Trends Parasitol 2019; 35:32-51. [DOI: 10.1016/j.pt.2018.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/07/2018] [Accepted: 10/08/2018] [Indexed: 12/16/2022]
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39
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Molecular tools and genetic markers for the generation of transgenic sexing strains in Anopheline mosquitoes. Parasit Vectors 2018; 11:660. [PMID: 30583738 PMCID: PMC6304780 DOI: 10.1186/s13071-018-3207-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Malaria is a serious global health burden, affecting more than 200 million people each year in over 90 countries, predominantly in Africa, Asia and the Americas. Since the year 2000, a concerted effort to combat malaria has reduced its incidence by more than 40%, primarily due to the use of insecticide-treated bednets, indoor residual spraying and artemisinin-based combination drug therapies. Nevertheless, the cost of control is expected to nearly triple over the next decade and the current downward trend in disease transmission is threatened by the rise of resistance to drugs and insecticides. Novel strategies that are sustainable and cost-effective are needed to help usher in an era of malaria elimination. The most effective strategies thus far have focussed on control of the mosquito vector. The sterile insect technique (SIT) is a potentially powerful strategy that aims to suppress mosquito populations through the unproductive mating of wild female mosquitoes with sterile males that are released en masse. The technique and its derivatives are currently not appropriate for malaria control because it is difficult to sterilise males without compromising their ability to mate, and because anopheline males cannot be easily separated from females, which if released, could contribute to disease transmission. Advances in genome sequencing technologies and the development of transgenic techniques provide the tools necessary to produce mosquito sexing strains, which promise to improve current malaria-control programs and pave the way for new ones. In this review, the progress made in the development of transgenic sexing strains for the control of Anopheles gambiae, a major vector of human malaria, is discussed.
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40
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Papathanos PA, Bourtzis K, Tripet F, Bossin H, Virginio JF, Capurro ML, Pedrosa MC, Guindo A, Sylla L, Coulibaly MB, Yao FA, Epopa PS, Diabate A. A perspective on the need and current status of efficient sex separation methods for mosquito genetic control. Parasit Vectors 2018; 11:654. [PMID: 30583720 PMCID: PMC6304774 DOI: 10.1186/s13071-018-3222-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Major efforts are currently underway to develop novel, complementary methods to combat mosquito-borne diseases. Mosquito genetic control strategies (GCSs) have become an increasingly important area of research on account of their species-specificity, track record in targeting agricultural insect pests, and their environmentally non-polluting nature. A number of programs targeting Aedes and Anopheles mosquitoes, vectors of human arboviruses and malaria respectively, are currently being developed or deployed in many parts of the world. Operationally implementing these technologies on a large scale however, beyond proof-of-concept pilot programs, is hampered by the absence of adequate sex separation methods. Sex separation eliminates females in the laboratory from male mosquitoes prior to release. Despite the need for sex separation for the control of mosquitoes, there have been limited efforts in recent years in developing systems that are fit-for-purpose. In this special issue of Parasites and Vectors we report on the progress of the global Coordinated Research Program on “Exploring genetic, molecular, mechanical and behavioural methods for sex separation in mosquitoes” that is led by the Insect Pest Control Subprogramme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture with the specific aim of building efficient sex separation systems for mosquito species. In an effort to overcome current barriers we briefly highlight what we believe are the three main reasons why progress has been so slow in developing appropriate sex separation systems: the availability of methods that are not scalable, the difficulty of building the ideal genetic systems and, finally, the lack of research efforts in this area.
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Affiliation(s)
- Philippos Aris Papathanos
- Department of Entomology, The Robert H Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel.
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, UK
| | - Hervé Bossin
- Laboratoire d'Entomologie Médicale, Institut Louis Malardé, BP 30, 98713, Papeete, French Polynesia.,Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée infection, Marseille, France
| | | | - Margareth Lara Capurro
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Michelle Cristine Pedrosa
- Biofabrica Moscamed Brazil, Industrial District, Juazeiro, BA, Brazil.,Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Amadou Guindo
- Malaria Research and Training Center, Université des Sciences, des Techniques et des Technologies de Bamako, Point G, Bamako, BP: 1805, Mali
| | - Lakamy Sylla
- Malaria Research and Training Center, Université des Sciences, des Techniques et des Technologies de Bamako, Point G, Bamako, BP: 1805, Mali
| | - Mamadou B Coulibaly
- Malaria Research and Training Center, Université des Sciences, des Techniques et des Technologies de Bamako, Point G, Bamako, BP: 1805, Mali
| | - Franck Adama Yao
- Institut de Recherche en Sciences de la Sante, Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Patric Stephane Epopa
- Institut de Recherche en Sciences de la Sante, Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Sante, Centre Muraz, Bobo-Dioulasso, Burkina Faso
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Mashatola T, Ndo C, Koekemoer LL, Dandalo LC, Wood OR, Malakoane L, Poumachu Y, Lobb LN, Kaiser M, Bourtzis K, Munhenga G. A review on the progress of sex-separation techniques for sterile insect technique applications against Anopheles arabiensis. Parasit Vectors 2018; 11:646. [PMID: 30583746 PMCID: PMC6304763 DOI: 10.1186/s13071-018-3219-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The feasibility of the sterile insect technique (SIT) as a malaria vector control strategy against Anopheles arabiensis has been under investigation over the past decade. One of the critical steps required for the application of this technique to mosquito control is the availability of an efficient and effective sex-separation system. Sex-separation systems eliminate female mosquitoes from the production line prior to irradiation and field release of sterile males. This is necessary because female mosquitoes can transmit pathogens such as malaria and, therefore, their release must be prevented. Sex separation also increases the efficiency of an SIT programme. Various sex-separation strategies have been explored including the exploitation of developmental and behavioural differences between male and female mosquitoes, and genetic approaches. Most of these are however species-specific and are not indicated for the major African malaria vectors such as An. arabiensis. As there is currently no reliable sex-separation method for An. arabiensis, various strategies were explored in an attempt to develop a robust system that can be applied on a mass-rearing scale. The progress and challenges faced during the development of a sexing system for future pilot and/or large-scale SIT release programmes against An. arabiensis are reviewed here. Three methods of sex separation were examined. The first is the use of pupal size for gender prediction. The second is the elimination of blood-feeding adult females through the addition of an endectocide to a blood meal source. The third is the establishment of a genetic sexing strain (GSS) carrying an insecticide resistance selectable marker (dieldrin-resistance rdl gene and/or other GABA receptor antagonists that can be used as alternative insecticides to dieldrin) or a temperature-sensitive lethal marker.
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Affiliation(s)
- Thabo Mashatola
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Cyrille Ndo
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Centre for Research in Infectious Disease (CRI), Yaoundé, Cameroon
| | - Lizette L. Koekemoer
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Leonard C. Dandalo
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Oliver R. Wood
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lerato Malakoane
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Yacouba Poumachu
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Vector Borne Disease Laboratory of the Applied Biology and Ecology Research Unit (VBDL-URBEA) Department of Animal Biology, Faculty of Sciences of the University of Dschang, Dschang, Cameroon
| | - Leanne N. Lobb
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Maria Kaiser
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Givemore Munhenga
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Miller JR, Koren S, Dilley KA, Puri V, Brown DM, Harkins DM, Thibaud-Nissen F, Rosen B, Chen XG, Tu Z, Sharakhov IV, Sharakhova MV, Sebra R, Stockwell TB, Bergman NH, Sutton GG, Phillippy AM, Piermarini PM, Shabman RS. Analysis of the Aedes albopictus C6/36 genome provides insight into cell line utility for viral propagation. Gigascience 2018; 7:1-13. [PMID: 29329394 PMCID: PMC5869287 DOI: 10.1093/gigascience/gix135] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 12/23/2017] [Indexed: 12/25/2022] Open
Abstract
Background The 50-year-old Aedes albopictus C6/36 cell line is a resource for the detection, amplification, and analysis of mosquito-borne viruses including Zika, dengue, and chikungunya. The cell line is derived from an unknown number of larvae from an unspecified strain of Aedes albopictus mosquitoes. Toward improved utility of the cell line for research in virus transmission, we present an annotated assembly of the C6/36 genome. Results The C6/36 genome assembly has the largest contig N50 (3.3 Mbp) of any mosquito assembly, presents the sequences of both haplotypes for most of the diploid genome, reveals independent null mutations in both alleles of the Dicer locus, and indicates a male-specific genome. Gene annotation was computed with publicly available mosquito transcript sequences. Gene expression data from cell line RNA sequence identified enrichment of growth-related pathways and conspicuous deficiency in aquaporins and inward rectifier K+ channels. As a test of utility, RNA sequence data from Zika-infected cells were mapped to the C6/36 genome and transcriptome assemblies. Host subtraction reduced the data set by 89%, enabling faster characterization of nonhost reads. Conclusions The C6/36 genome sequence and annotation should enable additional uses of the cell line to study arbovirus vector interactions and interventions aimed at restricting the spread of human disease.
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Affiliation(s)
- Jason R Miller
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA.,College of Natural Sciences and Mathematics, Shepherd University, Shepherdstown, WV 25443, USA
| | - Sergey Koren
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Kari A Dilley
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | - Vinita Puri
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | - David M Brown
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | - Derek M Harkins
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | | | - Benjamin Rosen
- USDA 10300 Baltimore Ave., Bldg 306 Barc-East, Beltsville, MD 20705-2350, USA
| | - Xiao-Guang Chen
- Department of Pathogen Biology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Zhijian Tu
- Department of Biochemistry and the Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA
| | - Igor V Sharakhov
- Department of Entomology and the Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.,Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Maria V Sharakhova
- Department of Entomology and the Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.,Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Robert Sebra
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | | | - Granger G Sutton
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | - Adam M Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Peter M Piermarini
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA.,Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA
| | - Reed S Shabman
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA.,ATCC, 217 Perry Parkway, Gaithersburg, MD 20877, USA
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43
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Deitz KC, Takken W, Slotman MA. The Effect of Hybridization on Dosage Compensation in Member Species of the Anopheles gambiae Species Complex. Genome Biol Evol 2018; 10:1663-1672. [PMID: 29860336 PMCID: PMC6037052 DOI: 10.1093/gbe/evy108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2018] [Indexed: 12/17/2022] Open
Abstract
Dosage compensation has evolved in concert with Y-chromosome degeneration in many taxa that exhibit heterogametic sex chromosomes. Dosage compensation overcomes the biological challenge of a “half dose” of X chromosome gene transcripts in the heterogametic sex. The need to equalize gene expression of a hemizygous X with that of autosomes arises from the fact that the X chromosomes retain hundreds of functional genes that are actively transcribed in both sexes and interact with genes expressed on the autosomes. Sex determination and heterogametic sex chromosomes have evolved multiple times in Diptera, and in each case the genetic control of dosage compensation is tightly linked to sex determination. In the Anopheles gambiae species complex (Culicidae), maleness is conferred by the Y-chromosome gene Yob, which despite its conserved role between species is polymorphic in its copy number between them. Previous work demonstrated that male An. gambiae s.s. males exhibit complete dosage compensation in pupal and adult stages. In the present study, we have extended this analysis to three sister species in the An. gambiae complex: An. coluzzii, An. arabiensis, and An. quadriannulatus. In addition, we analyzed dosage compensation in bi-directional F1 hybrids between these species to determine if hybridization results in the mis-regulation and disruption of dosage compensation. Our results confirm that dosage compensation operates in the An. gambiae species complex through the hypertranscription of the male X chromosome. Additionally, dosage compensation in hybrid males does not differ from parental males, indicating that hybridization does not result in the mis-regulation of dosage compensation.
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Affiliation(s)
- Kevin C Deitz
- Department of Entomology, Texas A&M University.,Department of Ecology and Evolutionary Biology and The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ
| | - Willem Takken
- Laboratory of Entomology, Department of Plant Sciences, Wageningen University, The Netherlands
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44
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Turner J, Krishna R, Van't Hof AE, Sutton ER, Matzen K, Darby AC. The sequence of a male-specific genome region containing the sex determination switch in Aedes aegypti. Parasit Vectors 2018; 11:549. [PMID: 30342535 PMCID: PMC6195999 DOI: 10.1186/s13071-018-3090-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/31/2018] [Indexed: 11/26/2022] Open
Abstract
Background Aedes aegypti is the principal vector of several important arboviruses. Among the methods of vector control to limit transmission of disease are genetic strategies that involve the release of sterile or genetically modified non-biting males, which has generated interest in manipulating mosquito sex ratios. Sex determination in Ae. aegypti is controlled by a non-recombining Y chromosome-like region called the M locus, yet characterisation of this locus has been thwarted by the repetitive nature of the genome. In 2015, an M locus gene named Nix was identified that displays the qualities of a sex determination switch. Results With the use of a whole-genome bacterial artificial chromosome (BAC) library, we amplified and sequenced a ~200 kb region containing the male-determining gene Nix. In this study, we show that Nix is comprised of two exons separated by a 99 kb intron primarily composed of repetitive DNA, especially transposable elements. Conclusions Nix, an unusually large and highly repetitive gene, exhibits features in common with Y chromosome genes in other organisms. We speculate that the lack of recombination at the M locus has allowed the expansion of repeats in a manner characteristic of a sex-limited chromosome, in accordance with proposed models of sex chromosome evolution in insects. Electronic supplementary material The online version of this article (10.1186/s13071-018-3090-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joe Turner
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.,Oxitec Ltd., 71 Innovation Drive, Milton Park, Abingdon, OX14 4RQ, UK
| | - Ritesh Krishna
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.,IBM Research UK, STFC Daresbury Laboratory, Warrington, WA4 4AD, UK
| | - Arjen E Van't Hof
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Elizabeth R Sutton
- Oxitec Ltd., 71 Innovation Drive, Milton Park, Abingdon, OX14 4RQ, UK.,Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.,Sistemic, West of Scotland Science Park, Glasgow, G20 0SP, UK
| | - Kelly Matzen
- Oxitec Ltd., 71 Innovation Drive, Milton Park, Abingdon, OX14 4RQ, UK
| | - Alistair C Darby
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
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45
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Li S, Ajimura M, Chen Z, Liu J, Chen E, Guo H, Tadapatri V, Reddy CG, Zhang J, Kishino H, Abe H, Xia Q, Arunkumar KP, Mita K. A new approach for comprehensively describing heterogametic sex chromosomes. DNA Res 2018; 25:375-382. [PMID: 29617732 PMCID: PMC6105102 DOI: 10.1093/dnares/dsy010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/09/2018] [Indexed: 12/30/2022] Open
Abstract
Notwithstanding the rapid developments in sequencing techniques, Y and W sex chromosomes have still been mostly excluded from whole genome sequencing projects due to their high repetitive DNA content. Therefore, Y and W chromosomes are poorly described in most species despite their biological importance. Several methods were developed for identifying Y or W-linked sequences among unmapped scaffolds. However, it is not enough to discover functional regions from short unmapped scaffolds. Here, we provide a new and simple strategy based on k-mer comparison for comprehensive analysis of the W chromosome in Bombyx mori. Using this novel method, we effectively assembled de novo 1281 W-derived genome contigs (totaling 1.9 Mbp), and identified 156 W-linked transcript RNAs and 345 W-linked small RNAs. This method will help in the elucidation of mechanisms of sexual development and exploration of W chromosome biological functions, and provide insights into the evolution of sex chromosomes. Moreover, we showed this method can be employed in identifying heterogametic sex chromosomes (W and Y chromosomes) in many other species where genomic information is still scarce.
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Affiliation(s)
- Shenglong Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Masahiro Ajimura
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Zhiwei Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Jianqiu Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Enxiang Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Huizhen Guo
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Vidya Tadapatri
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Chilakala Gangi Reddy
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Jiwei Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Hirohisa Kishino
- Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
| | - Hiroaki Abe
- Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Kallare P Arunkumar
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Kazuei Mita
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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46
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De novo assembly of a young Drosophila Y chromosome using single-molecule sequencing and chromatin conformation capture. PLoS Biol 2018; 16:e2006348. [PMID: 30059545 PMCID: PMC6117089 DOI: 10.1371/journal.pbio.2006348] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 08/30/2018] [Accepted: 07/04/2018] [Indexed: 01/27/2023] Open
Abstract
While short-read sequencing technology has resulted in a sharp increase in the number of species with genome assemblies, these assemblies are typically highly fragmented. Repeats pose the largest challenge for reference genome assembly, and pericentromeric regions and the repeat-rich Y chromosome are typically ignored from sequencing projects. Here, we assemble the genome of Drosophila miranda using long reads for contig formation, chromatin interaction maps for scaffolding and short reads, and optical mapping and bacterial artificial chromosome (BAC) clone sequencing for consensus validation. Our assembly recovers entire chromosomes and contains large fractions of repetitive DNA, including about 41.5 Mb of pericentromeric and telomeric regions, and >100 Mb of the recently formed highly repetitive neo-Y chromosome. While Y chromosome evolution is typically characterized by global sequence loss and shrinkage, the neo-Y increased in size by almost 3-fold because of the accumulation of repetitive sequences. Our high-quality assembly allows us to reconstruct the chromosomal events that have led to the unusual sex chromosome karyotype in D. miranda, including the independent de novo formation of a pair of sex chromosomes at two distinct time points, or the reversion of a former Y chromosome to an autosome.
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47
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Wei KHC, Lower SE, Caldas IV, Sless TJS, Barbash DA, Clark AG. Variable Rates of Simple Satellite Gains across the Drosophila Phylogeny. Mol Biol Evol 2018; 35:925-941. [PMID: 29361128 PMCID: PMC5888958 DOI: 10.1093/molbev/msy005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Simple satellites are tandemly repeating short DNA motifs that can span megabases in eukaryotic genomes. Because they can cause genomic instability through nonallelic homologous exchange, they are primarily found in the repressive heterochromatin near centromeres and telomeres where recombination is minimal, and on the Y chromosome, where they accumulate as the chromosome degenerates. Interestingly, the types and abundances of simple satellites often vary dramatically between closely related species, suggesting that they turn over rapidly. However, limited sampling has prevented detailed understanding of their evolutionary dynamics. Here, we characterize simple satellites from whole-genome sequences generated from males and females of nine Drosophila species, spanning 40 Ma of evolution. We show that PCR-free library preparation and postsequencing GC-correction better capture satellite quantities than conventional methods. We find that over half of the 207 simple satellites identified are species-specific, consistent with previous descriptions of their rapid evolution. Based on a maximum parsimony framework, we determined that most interspecific differences are due to lineage-specific gains. Simple satellites gained within a species are typically a single mutation away from abundant existing satellites, suggesting that they likely emerge from existing satellites, especially in the genomes of satellite-rich species. Interestingly, unlike most of the other lineages which experience various degrees of gains, the lineage leading up to the satellite-poor D. pseudoobscura and D. persimilis appears to be recalcitrant to gains, providing a counterpoint to the notion that simple satellites are universally rapidly evolving.
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Affiliation(s)
- Kevin H -C Wei
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY
- Department of Integrative Biology, University of California, Berkeley, CA
| | - Sarah E Lower
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY
| | - Ian V Caldas
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY
| | - Trevor J S Sless
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY
| | - Daniel A Barbash
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY
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48
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Abstract
Drive is a process of accelerated inheritance from one generation to the next that allows some genes to spread rapidly through populations even if they do not contribute to-or indeed even if they detract from-organismal survival and reproduction. Genetic elements that can spread by drive include gametic and zygotic killers, meiotic drivers, homing endonuclease genes, B chromosomes, and transposable elements. The fact that gene drive can lead to the spread of fitness-reducing traits (including lethality and sterility) makes it an attractive process to consider exploiting to control disease vectors and other pests. There are a number of efforts to develop synthetic gene drive systems, particularly focused on the mosquito-borne diseases that continue to plague us.
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Affiliation(s)
- Austin Burt
- Life Sciences, Imperial College, Silwood Park, Ascot, SL5
7PY, United Kingdom
| | - Andrea Crisanti
- Life Sciences, Imperial College, South Kensington, London, SW7 2AZ, United Kingdom
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49
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Fontaine A, Filipovic I, Fansiri T, Hoffmann AA, Cheng C, Kirkpatrick M, Rašic G, Lambrechts L. Extensive Genetic Differentiation between Homomorphic Sex Chromosomes in the Mosquito Vector, Aedes aegypti. Genome Biol Evol 2018; 9:2322-2335. [PMID: 28945882 PMCID: PMC5737474 DOI: 10.1093/gbe/evx171] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2017] [Indexed: 12/25/2022] Open
Abstract
Mechanisms and evolutionary dynamics of sex-determination systems are of particular interest in insect vectors of human pathogens like mosquitoes because novel control strategies aim to convert pathogen-transmitting females into nonbiting males, or rely on accurate sexing for the release of sterile males. In Aedes aegypti, the main vector of dengue and Zika viruses, sex determination is governed by a dominant male-determining locus, previously thought to reside within a small, nonrecombining, sex-determining region (SDR) of an otherwise homomorphic sex chromosome. Here, we provide evidence that sex chromosomes in Ae. aegypti are genetically differentiated between males and females over a region much larger than the SDR. Our linkage mapping intercrosses failed to detect recombination between X and Y chromosomes over a 123-Mbp region (40% of their physical length) containing the SDR. This region of reduced male recombination overlapped with a smaller 63-Mbp region (20% of the physical length of the sex chromosomes) displaying high male–female genetic differentiation in unrelated wild populations from Brazil and Australia and in a reference laboratory strain originating from Africa. In addition, the sex-differentiated genomic region was associated with a significant excess of male-to-female heterozygosity and contained a small cluster of loci consistent with Y-specific null alleles. We demonstrate that genetic differentiation between sex chromosomes is sufficient to assign individuals to their correct sex with high accuracy. We also show how data on allele frequency differences between sexes can be used to estimate linkage disequilibrium between loci and the sex-determining locus. Our discovery of large-scale genetic differentiation between sex chromosomes in Ae. aegypti lays a new foundation for mapping and population genomic studies, as well as for mosquito control strategies targeting the sex-determination pathway.
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Affiliation(s)
- Albin Fontaine
- Department of Genomes and Genetics, Insect-Virus Interactions Group, Institut Pasteur, Paris, France.,Département des Maladies Infectieuses, Unité de Parasitologie et Entomologie, Institut de Recherche Biomédicale des Armées, Marseille, France.,Centre National de la Recherche Scientifique, URA 3012, Paris, France.,Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, AP-HM, IHU-Méditerranée Infection, France
| | - Igor Filipovic
- Pest and Environmental Adaptation Research Group, School of BioSciences and Bio21 Institute, Faculty of Science, The University of Melbourne, Victoria, Australia
| | - Thanyalak Fansiri
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Ary A Hoffmann
- Pest and Environmental Adaptation Research Group, School of BioSciences and Bio21 Institute, Faculty of Science, The University of Melbourne, Victoria, Australia
| | - Changde Cheng
- Department of Integrative Biology, University of Texas, Austin
| | | | - Gordana Rašic
- Pest and Environmental Adaptation Research Group, School of BioSciences and Bio21 Institute, Faculty of Science, The University of Melbourne, Victoria, Australia
| | - Louis Lambrechts
- Department of Genomes and Genetics, Insect-Virus Interactions Group, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, URA 3012, Paris, France
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50
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Papathanos PA, Windbichler N. Redkmer: An Assembly-Free Pipeline for the Identification of Abundant and Specific X-Chromosome Target Sequences for X-Shredding by CRISPR Endonucleases. CRISPR J 2018; 1:88-98. [PMID: 30627701 PMCID: PMC6319322 DOI: 10.1089/crispr.2017.0012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CRISPR-based synthetic sex ratio distorters, which operate by shredding the X-chromosome during male meiosis, are promising tools for the area-wide control of harmful insect pest or disease vector species. X-shredders have been proposed as tools to suppress insect populations by biasing the sex ratio of the wild population toward males, thus reducing its natural reproductive potential. However, to build synthetic X-shredders based on CRISPR, the selection of gRNA targets, in the form of high-copy sequence repeats on the X chromosome of a given species, is difficult, since such repeats are not accurately resolved in genome assemblies and cannot be assigned to chromosomes with confidence. We have therefore developed the redkmer computational pipeline, designed to identify short and highly abundant sequence elements occurring uniquely on the X chromosome. Redkmer was designed to use as input minimally processed whole genome sequence data from males and females. We tested redkmer with short- and long-read whole genome sequence data of Anopheles gambiae, the major vector of human malaria, in which the X-shredding paradigm was originally developed. Redkmer established long reads as chromosomal proxies with excellent correlation to the genome assembly and used them to rank X-candidate kmers for their level of X-specificity and abundance. Among these, a high-confidence set of 25-mers was identified, many belonging to previously known X-chromosome repeats of Anopheles gambiae, including the ribosomal gene array and the selfish elements harbored within it. Data from a control strain, in which these repeats are shared with the Y chromosome, confirmed the elimination of these kmers during filtering. Finally, we show that redkmer output can be linked directly to gRNA selection and off-target prediction. In addition, the output of redkmer, including the prediction of chromosomal origin of single-molecule long reads and chromosome specific kmers, could also be used for the characterization of other biologically relevant sex chromosome sequences, a task that is frequently hampered by the repetitiveness of sex chromosome sequence content.
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Affiliation(s)
- Philippos Aris Papathanos
- Department of Experimental Medicine, Section of Genomics and Genetics, University of Perugia, Perugia, Italy
| | - Nikolai Windbichler
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London, United Kingdom
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