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Pollegioni P, Persampieri T, Minuz RL, Bucci A, Trusso A, Martino SD, Leo C, Bruttini M, Ciolfi M, Waldvogel A, Tripet F, Simoni A, Crisanti A, Müller R. Introgression of a synthetic sex ratio distortion transgene into different genetic backgrounds of Anopheles coluzzii. INSECT MOLECULAR BIOLOGY 2023; 32:56-68. [PMID: 36251429 PMCID: PMC10092091 DOI: 10.1111/imb.12813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The development of genetically modified mosquitoes (GMM) and their subsequent field release offers innovative approaches for vector control of malaria. A non-gene drive self-limiting male-bias Ag(PMB)1 strain has been developed in a 47-year-old laboratory G3 strain of Anopheles gambiae s.l. When Ag(PMB)1 males are crossed to wild-type females, expression of the endonuclease I-PpoI during spermatogenesis causes the meiotic cleavage of the X chromosome in sperm cells, leading to fertile offspring with a 95% male bias. However, World Health Organization states that the functionality of the transgene could differ when inserted in different genetic backgrounds of Anopheles coluzzii which is currently a predominant species in several West-African countries and thus a likely recipient for a potential release of self-limiting GMMs. In this study, we introgressed the transgene from the donor Ag(PMB)1 by six serial backcrosses into two recipient colonies of An. coluzzii that had been isolated in Mali and Burkina Faso. Scans of informative Single Nucleotide Polymorphism (SNP) markers and whole-genome sequencing analysis revealed a nearly complete introgression of chromosomes 3 and X, but a remarkable genomic divergence in a large region of chromosome 2 between the later backcrossed (BC6) transgenic offspring and the recipient paternal strains. These findings suggested to extend the backcrossing breeding strategy beyond BC6 generation and increasing the introgression efficiency of critical regions that have ecological and epidemiological implications through the targeted selection of specific markers. Disregarding differential introgression efficiency, we concluded that the phenotype of the sex ratio distorter is stable in the BC6 introgressed An. coluzzii strains.
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Affiliation(s)
- Paola Pollegioni
- Research Institute on Terrestrial EcosystemsNational Research CouncilTerniItaly
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Tania Persampieri
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Roxana L. Minuz
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Alessandro Bucci
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Alessandro Trusso
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Salvatore Di Martino
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Chiara Leo
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Marco Bruttini
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
- Tuscan Centre of Precision Medicine, Department of Medicine, Surgery and NeurosciencesUniversity of SienaSienaItaly
| | - Marco Ciolfi
- Research Institute on Terrestrial EcosystemsNational Research CouncilTerniItaly
| | | | - Frédéric Tripet
- Centre for Applied Entomology and ParasitologyKeele UniversityNewcastle‐under‐LymeUK
| | - Alekos Simoni
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Andrea Crisanti
- Department of Molecular MedicineUniversity of PadovaPadovaItaly
| | - Ruth Müller
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
- Unit Entomology, Department of Biomedical SciencesInstitute of Tropical MedicineAntwerpBelgium
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Zhang J, Zhang S, Zheng Z, Lu Z, Yang Y. Genomic divergence between two sister Ostrya species through linked selection and recombination. Ecol Evol 2022; 12:e9611. [PMID: 36540075 PMCID: PMC9754895 DOI: 10.1002/ece3.9611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/16/2022] [Accepted: 11/22/2022] [Indexed: 12/23/2022] Open
Abstract
Studying the evolution of genomic divergence between lineages is a topical issue in evolutionary biology. However, the evolutionary forces that shape the heterogeneous divergence of the genomic landscape are still poorly understood. Here, two wind-pollinated sister-species (Ostrya japonica and O. chinensis) are used to explore what these potential forces might be. A total of 40 individuals from 16 populations across their main distribution areas in China were sampled for genome-wide resequencing. Population demography analyses revealed that these two sister-species diverged at 3.06-4.43 Mya. Both population contraction and increased gene flow were detected during glacial periods, suggesting secondary contact at those times. All three parameters (D XY, π, and ρ) decreased in those regions showing high levels of differentiation (F ST). These findings indicate that linked selection and recombination played a key role in the genomic heterogeneous differentiation between the two Ostrya species. Genotype-environment association analyses showed that precipitation was the most important ecological factor for speciation. Such environmentally related genes and positive selection genes may have contributed to local adaptation and the maintenance of species boundaries.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Grassland Agro‐Ecosystems, College of EcologyLanzhou UniversityLanzhouChina
| | - Shangzhe Zhang
- State Key Laboratory of Grassland Agro‐Ecosystems, College of EcologyLanzhou UniversityLanzhouChina
| | - Zeyu Zheng
- State Key Laboratory of Grassland Agro‐Ecosystems, College of EcologyLanzhou UniversityLanzhouChina
| | - Zhiqiang Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
| | - Yongzhi Yang
- State Key Laboratory of Grassland Agro‐Ecosystems, College of EcologyLanzhou UniversityLanzhouChina
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Eggleston H, Njoya K, Anderson CE, Holm I, Eiglmeier K, Liang J, Sharakhov IV, Vernick KD, Riehle MM. Molecular characterization and genetic authentication assay for Anopheles 'hemocyte-like' cell lines 4a-3A and 4a-3B. Parasit Vectors 2022; 15:465. [PMID: 36514125 PMCID: PMC9749150 DOI: 10.1186/s13071-022-05590-3] [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: 08/19/2022] [Accepted: 11/15/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Anopheles cell lines are used in a variety of ways to better understand the major vectors of malaria in sub-Saharan Africa. Despite this, commonly used cell lines are not well characterized, and no tools are available for cell line identification and authentication. METHODS Utilizing whole genome sequencing, genomes of 4a-3A and 4a-3B 'hemocyte-like' cell lines were characterized for insertions and deletions (indels) and SNP variation. Genomic locations of distinguishing sequence variation and species origin of the cell lines were also examined. Unique indels were targeted to develop a PCR-based cell line authentication assay. Mitotic chromosomes were examined to survey the cytogenetic landscape for chromosome structure and copy number in the cell lines. RESULTS The 4a-3A and 4a-3B cell lines are female in origin and primarily of Anopheles coluzzii ancestry. Cytogenetic analysis indicates that the two cell lines are essentially diploid, with some relatively minor chromosome structural rearrangements. Whole-genome sequence was generated, and analysis indicated that SNPs and indels which differentiate the cell lines are clustered on the 2R chromosome in the regions of the 2Rb, 2Rc and 2Ru chromosomal inversions. A PCR-based authentication assay was developed to fingerprint three indels unique to each cell line. The assay distinguishes between 4a-3A and 4a-3B cells and also uniquely identifies two additional An. coluzzii cell lines tested, Ag55 and Sua4.0. The assay has the specificity to distinguish four cell lines and also has the sensitivity to detect cellular contamination within a sample of cultured cells. CONCLUSIONS Genomic characterization of the 4a-3A and 4a-3B Anopheles cell lines was used to develop a simple diagnostic assay that can distinguish these cell lines within and across research laboratories. A cytogenetic survey indicated that the 4a-3A and Sua4.0 cell lines carry essentially normal diploid chromosomes, which makes them amenable to CRISPR/Cas9 genome editing. The presented simple authentication assay, coupled with screening for mycoplasma, will allow validation of the integrity of experimental resources and will promote greater experimental reproducibility of results.
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Affiliation(s)
- Heather Eggleston
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kimani Njoya
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Cameron E Anderson
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Inge Holm
- Institut Pasteur, Université de Paris, CNRS UMR 2000, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
| | - Karin Eiglmeier
- Institut Pasteur, Université de Paris, CNRS UMR 2000, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
| | - Jiangtao Liang
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Kenneth D Vernick
- Institut Pasteur, Université de Paris, CNRS UMR 2000, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
| | - Michelle M Riehle
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA.
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Sangbakembi-Ngounou C, Ngoagouni C, Akone-Ella O, Kengne P, Costantini C, Nakouné E, Ayala D. Temporal and biting dynamics of the chromosomal inversion 2La in the malaria vectors Anopheles gambiae and Anopheles coluzzii in Bangui, Central African Republic. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.986925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The chromosomal rearrangement 2La has been directly involved in the ecological and deadly epidemiological success of the malaria mosquitoes Anopheles gambiae and Anopheles coluzzii in sub-Saharan Africa. However, little is known about the biological and ecological factors that drive the local and temporal dynamics of this inversion in both species. Here, we performed a year-round longitudinal survey in Bangui, Central African Republic. We monthly sampled A. gambiae and A. coluzzii mosquitoes indoor and outdoor using human landing catches (HLC) for 48 h non-stop. We molecularly karyotyped all specimens to study the 2La inversion frequency variations, and monitored the mosquito spatial and temporal biting behavior throughout the year. In total, we successfully karyotyped 5121 A. gambiae and 986 A. coluzzii specimens. The 2La inversion frequency was higher in A. coluzzii than in A. gambiae across the year. In A. gambiae and A. coluzzii, the inversion frequency or karyotypes did not influence the biting behavior, either location or time. Moreover, the inversion frequency variation in both species was also independent of local climatic changes. Overall, our results revealed that in Bangui, the 2La inversion segregates at different frequency in each species, but this is not influenced by their trophic behavior. Studying the impact of urban settings and the population genetic structure of these two A. gambiae complex members could bring insights into the intrinsic relationship between 2La inversion and local conditions. More studies are needed to understand the polymorphic equilibrium of this inversion in Bangui.
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Perfect association between spatial swarm segregation and the X-chromosome speciation island in hybridizing Anopheles coluzzii and Anopheles gambiae populations. Sci Rep 2022; 12:10800. [PMID: 35750745 PMCID: PMC9232630 DOI: 10.1038/s41598-022-14865-9] [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: 03/08/2022] [Accepted: 06/14/2022] [Indexed: 11/08/2022] Open
Abstract
The sibling species An. coluzzii and An. gambiae s.s. are major malaria vectors thought to be undergoing sympatric speciation with gene flow. In the absence of intrinsic post-zygotic isolation between the two taxa, speciation is thought possible through the association of assortative mating and genomic regions protected from gene flow by recombination suppression. Such genomic islands of speciation have been described in pericentromeric regions of the X, 2L and 3L chromosomes. Spatial swarm segregation plays a major role in assortative mating between sympatric populations of the two species and, given their importance for speciation, genes responsible for such pre-mating reproductive barriers are expected to be protected within divergence islands. In this study 2063 male and 266 female An. coluzzii and An. gambiae s.s. individuals from natural swarms in Burkina Faso, West Africa were sampled. These were genotyped at 16 speciation island SNPs, and characterized as non-hybrid individuals, F1 hybrids or recombinant F1+n backcrossed individuals. Their genotypes at each speciation island were associated with their participation in An. coluzzii and An. gambiae-like swarms. Despite extensive introgression between the two species, the X-island genotype of non-hybrid individuals (37.6%), F1 hybrids (0.1%) and F1+n recombinants (62.3%) of either sex perfectly associated to each swarm type. Associations between swarm type and the 3L and 2L speciation islands were weakened or broken down by introgression. The functional demonstration of a close association between spatial segregation behaviour and the X speciation island lends further support to sympatric speciation models facilitated by pericentric recombination suppression in this important species complex.
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Caputo B, Tondossoma N, Virgillito C, Pichler V, Serini P, Calzetta M, Manica M, Coulibaly ZI, Dia I, Akré M, Offianan A, Della Torre A. Is Côte D'Ivoire a new high hybridization zone for the two major malaria vectors, Anopheles coluzzii and An. gambiae (Diptera, Culicidae)? INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 98:105215. [PMID: 35063691 DOI: 10.1016/j.meegid.2022.105215] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Anopheles gambiae and An. coluzzii are very closely related and recently differentiated species representing the main malaria vectors in the Afrotropical region and responsible of up to >3 infective bites/person/night in Côte D'Ivoire, where prevention and control has stagnated in recent years. The aim of the present study was to genetically and ecologically characterize An. gambiae and An. coluzzii populations from two villages of Côte D'Ivoire, lying in the coastal forest belt and 250 km inland in the Guinean savannah mosaic belt, respectively. Results reveal high frequencies of both species in both study sites and high frequencies of hybrids (4-33%) along the whole year of sampling. Consistently with observations for the well-known high hybridization zone at the far-west of the species range, hybrid frequencies were higher in the coastal village and highest when the two species occurred at more balanced frequencies, supporting the "frequency-dependent hybridization" ecological speciation theory. Pilot genotyping revealed signatures of genomic admixture in both chromosome-X and -3. Coupled with previous reports of hybrids in the region, the results point to the coastal region of Côte D'Ivoire as a possible regions of high hybridization. Preliminary characterization of parameters relevant for malaria transmission and control (e.g. possibly higher sporozoite rates and indoor biting preferences in hybrids than in the parental species) highlight the possible relevance of the breakdown of reproductive barriers between An. gambiae and An. coluzzii not only in the field of ecological evolution, but also in malaria epidemiology and control.
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Affiliation(s)
- Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy.
| | - Naminata Tondossoma
- Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire; Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire
| | - Chiara Virgillito
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy; Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire; Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire; Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, TN, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Paola Serini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Maria Calzetta
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Mattia Manica
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, TN, Italy; Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | | | - Ibrahima Dia
- Unité d'entomologie médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, Dakar, BP 220, Senegal
| | - Maurice Akré
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire
| | - Andre Offianan
- Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
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The Build-Up of Population Genetic Divergence along the Speciation Continuum during a Recent Adaptive Radiation of Rhagoletis Flies. Genes (Basel) 2022; 13:genes13020275. [PMID: 35205320 PMCID: PMC8872456 DOI: 10.3390/genes13020275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 02/05/2023] Open
Abstract
New species form through the evolution of genetic barriers to gene flow between previously interbreeding populations. The understanding of how speciation proceeds is hampered by our inability to follow cases of incipient speciation through time. Comparative approaches examining different diverging taxa may offer limited inferences, unless they fulfill criteria that make the comparisons relevant. Here, we test for those criteria in a recent adaptive radiation of the Rhagoletis pomonella species group (RPSG) hypothesized to have diverged in sympatry via adaptation to different host fruits. We use a large-scale population genetic survey of 1568 flies across 33 populations to: (1) detect on-going hybridization, (2) determine whether the RPSG is derived from the same proximate ancestor, and (3) examine patterns of clustering and differentiation among sympatric populations. We find that divergence of each in-group RPSG taxon is occurring under current gene flow, that the derived members are nested within the large pool of genetic variation present in hawthorn-infesting populations of R. pomonella, and that sympatric population pairs differ markedly in their degree of genotypic clustering and differentiation across loci. We conclude that the RPSG provides a particularly robust opportunity to make direct comparisons to test hypotheses about how ecological speciation proceeds despite on-going gene flow.
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Campos M, Rona LDP, Willis K, Christophides GK, MacCallum RM. Unravelling population structure heterogeneity within the genome of the malaria vector Anopheles gambiae. BMC Genomics 2021; 22:422. [PMID: 34103015 PMCID: PMC8185951 DOI: 10.1186/s12864-021-07722-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 05/18/2021] [Indexed: 12/26/2022] Open
Abstract
Background Whole genome re-sequencing provides powerful data for population genomic studies, allowing robust inferences of population structure, gene flow and evolutionary history. For the major malaria vector in Africa, Anopheles gambiae, other genetic aspects such as selection and adaptation are also important. In the present study, we explore population genetic variation from genome-wide sequencing of 765 An. gambiae and An. coluzzii specimens collected from across Africa. We used t-SNE, a recently popularized dimensionality reduction method, to create a 2D-map of An. gambiae and An. coluzzii genes that reflect their population structure similarities. Results The map allows intuitive navigation among genes distributed throughout the so-called “mainland” and numerous surrounding “island-like” gene clusters. These gene clusters of various sizes correspond predominantly to low recombination genomic regions such as inversions and centromeres, and also to recent selective sweeps. Because this mosquito species complex has been studied extensively, we were able to support our interpretations with previously published findings. Several novel observations and hypotheses are also made, including selective sweeps and a multi-locus selection event in Guinea-Bissau, a known intense hybridization zone between An. gambiae and An. coluzzii. Conclusions Our results present a rich dataset that could be utilized in functional investigations aiming to shed light onto An. gambiae s.l genome evolution and eventual speciation. In addition, the methodology presented here can be used to further characterize other species not so well studied as An. gambiae, shortening the time required to progress from field sampling to the identification of genes and genomic regions under unique evolutionary processes. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07722-y.
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Affiliation(s)
- Melina Campos
- Department of Life Sciences, Imperial College London, London, UK
| | - Luisa D P Rona
- Department of Life Sciences, Imperial College London, London, UK.,Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil.,National Institute of Science and Technology in Molecular Entomology, National Council for Scientific and Technological Development (INCT-EM, CNPq), Rio de Janeiro, Brazil
| | - Katie Willis
- Department of Life Sciences, Imperial College London, London, UK
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Bourgeois YXC, Warren BH. An overview of current population genomics methods for the analysis of whole-genome resequencing data in eukaryotes. Mol Ecol 2021; 30:6036-6071. [PMID: 34009688 DOI: 10.1111/mec.15989] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/26/2021] [Accepted: 05/11/2021] [Indexed: 01/01/2023]
Abstract
Characterizing the population history of a species and identifying loci underlying local adaptation is crucial in functional ecology, evolutionary biology, conservation and agronomy. The constant improvement of high-throughput sequencing techniques has facilitated the production of whole genome data in a wide range of species. Population genomics now provides tools to better integrate selection into a historical framework, and take into account selection when reconstructing demographic history. However, this improvement has come with a profusion of analytical tools that can confuse and discourage users. Such confusion limits the amount of information effectively retrieved from complex genomic data sets, and impairs the diffusion of the most recent analytical tools into fields such as conservation biology. It may also lead to redundancy among methods. To address these isssues, we propose an overview of more than 100 state-of-the-art methods that can deal with whole genome data. We summarize the strategies they use to infer demographic history and selection, and discuss some of their limitations. A website listing these methods is available at www.methodspopgen.com.
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Affiliation(s)
| | - Ben H Warren
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, UA, CP 51, Paris, France
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10
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Caputo B, Pichler V, Bottà G, De Marco C, Hubbart C, Perugini E, Pinto J, Rockett KA, Miles A, Della Torre A. Novel genotyping approaches to easily detect genomic admixture between the major Afrotropical malaria vector species, Anopheles coluzzii and An. gambiae. Mol Ecol Resour 2021; 21:1504-1516. [PMID: 33590707 PMCID: PMC8252489 DOI: 10.1111/1755-0998.13359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 11/28/2022]
Abstract
The two most efficient and most recently radiated Afrotropical vectors of human malaria - Anopheles coluzzii and An. gambiae - are identified by single-locus diagnostic PCR assays based on species-specific markers in a 4 Mb region on chromosome-X centromere. Inherently, these diagnostic assays cannot detect interspecific autosomal admixture shown to be extensive at the westernmost and easternmost extremes of the species range. The main aim of this study was to develop novel, easy-to-implement tools for genotyping An. coluzzii and An. gambiae-specific ancestral informative markers (AIMs) identified from the Anopheles gambiae 1000 genomes (Ag1000G) project. First, we took advantage of this large set of data in order to develop a multilocus approach to genotype 26 AIMs on all chromosome arms valid across the species range. Second, we tested the multilocus assay on samples from Guinea Bissau, The Gambia and Senegal, three countries spanning the westernmost hybridization zone, where conventional species diagnostic is problematic due to the putative presence of a novel "hybrid form". The multilocus assay was able to capture patterns of admixture reflecting those revealed by the whole set of AIMs and provided new original data on interspecific admixture in the region. Third, we developed an easy-to-use, cost-effective PCR approach for genotyping two AIMs on chromosome-3 among those included in the multilocus approach, opening the possibility for advanced identification of species and of admixed specimens during routine large scale entomological surveys, particularly, but not exclusively, at the extremes of the range, where WGS data highlighted unexpected autosomal admixture.
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Affiliation(s)
- Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy
| | - Giordano Bottà
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy.,Wellcome Centre for Human Genetics, University of Oxford, Headington, Oxford, UK
| | - Carlo De Marco
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy
| | - Christina Hubbart
- Wellcome Centre for Human Genetics, University of Oxford, Headington, Oxford, UK
| | - Eleonora Perugini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy
| | - Joao Pinto
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Kirk A Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Headington, Oxford, UK
| | - Alistair Miles
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "Sapienza", Rome, Italy
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11
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Evidence for Divergent Selection on Immune Genes between the African Malaria Vectors, Anopheles coluzzii and A. gambiae. INSECTS 2020; 11:insects11120893. [PMID: 33352887 PMCID: PMC7767042 DOI: 10.3390/insects11120893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 11/20/2022]
Abstract
Simple Summary A comparison of the genomes of the African malaria vectors, Anopheles gambiae and A. coluzzii, revealed that immune genes are highly diverged. Although these two species frequently co-occur within a single site, they occur in distinct larval habitats. Our results taken in the context of known differences in the larval habitats occupied by these taxa support the hypothesis that observed genetic divergence may be driven by immune response to microbial agents specific to these habitats. Strict within species mating may have subsequently evolved in part to maintain immunocompetence which might be compromised by dysregulation of immune pathways in hybrids. We conclude that the evolution of immune gene divergence among this important group of species may serve as a useful model to explore ecological speciation in general. Abstract During their life cycles, microbes infecting mosquitoes encounter components of the mosquito anti-microbial innate immune defenses. Many of these immune responses also mediate susceptibility to malaria parasite infection. In West Africa, the primary malaria vectors are Anopheles coluzzii and A. gambiae sensu stricto, which is subdivided into the Bamako and Savanna sub-taxa. Here, we performed whole genome comparisons of the three taxa as well as genotyping of 333 putatively functional SNPs located in 58 immune signaling genes. Genome data support significantly higher differentiation in immune genes compared with a randomly selected set of non-immune genes among the three taxa (permutation test p < 0.001). Among the 58 genes studied, the majority had one or more segregating mutations (72.9%) that were significantly diverged among the three taxa. Genes detected to be under selection include MAP2K4 and Raf. Despite the genome-wide distribution of immune genes, a high level of linkage disequilibrium (r2 > 0.8) was detected in over 27% of SNP pairs. We discuss the potential role of immune gene divergence as adaptations to the different larval habitats associated with A. gambiae taxa and as a potential force driving ecological speciation in this group of mosquitoes.
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12
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Zheng XL. Unveiling mosquito cryptic species and their reproductive isolation. INSECT MOLECULAR BIOLOGY 2020; 29:499-510. [PMID: 32741005 PMCID: PMC7754467 DOI: 10.1111/imb.12666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/04/2020] [Accepted: 07/18/2020] [Indexed: 06/11/2023]
Abstract
Mosquitoes are major vectors of many infectious pathogens or parasites. Understanding cryptic species and the speciation of disease vectors has important implications for vector management, evolution and host-pathogen and/or host-parasite interactions. Currently, mosquito cryptic species have been reported in many studies, most of which focus on the reproductive isolation of cryptic species and mainly on Anopheles gambiae sensu lato complex. Emerging species within the primary malaria vector Anopheles gambiae show different ecological preferences and significant prezygotic reproductive isolation, while Aedes mariae and Aedes zammitii show postmating reproductive isolation. However, data reporting the reproductive isolation in Culex and Aedes albopictus mosquito cryptic species is absent. The lack of systematic studies leaves many questions open, such as whether cryptic species are more common in particular habitats, latitudes or taxonomic groups; what mosquito cryptic species evolutionary processes bring about reproductive isolation in the absence of morphological differentiation? How does Wolbachia infection affect in mosquitoes' reproductive isolation? In this review, we provide a summary of recent advances in the discovery and identification of sibling or cryptic species within mosquito genera.
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Affiliation(s)
- XL. Zheng
- Department of Pathogen Biology, School of Public HealthSouthern Medical UniversityGuangzhouChina
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13
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Genomic islands of differentiation in a rapid avian radiation have been driven by recent selective sweeps. Proc Natl Acad Sci U S A 2020; 117:30554-30565. [PMID: 33199636 DOI: 10.1073/pnas.2015987117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Numerous studies of emerging species have identified genomic "islands" of elevated differentiation against a background of relative homogeneity. The causes of these islands remain unclear, however, with some signs pointing toward "speciation genes" that locally restrict gene flow and others suggesting selective sweeps that have occurred within nascent species after speciation. Here, we examine this question through the lens of genome sequence data for five species of southern capuchino seedeaters, finch-like birds from South America that have undergone a species radiation during the last ∼50,000 generations. By applying newly developed statistical methods for ancestral recombination graph inference and machine-learning methods for the prediction of selective sweeps, we show that previously identified islands of differentiation in these birds appear to be generally associated with relatively recent, species-specific selective sweeps, most of which are predicted to be soft sweeps acting on standing genetic variation. Many of these sweeps coincide with genes associated with melanin-based variation in plumage, suggesting a prominent role for sexual selection. At the same time, a few loci also exhibit indications of possible selection against gene flow. These observations shed light on the complex manner in which natural selection shapes genome sequences during speciation.
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14
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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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15
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Rifkin JL, Castillo AS, Liao IT, Rausher MD. Gene flow, divergent selection and resistance to introgression in two species of morning glories (Ipomoea). Mol Ecol 2019; 28:1709-1729. [PMID: 30451335 DOI: 10.1111/mec.14945] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 09/03/2018] [Accepted: 11/01/2018] [Indexed: 02/03/2023]
Abstract
Gene flow is thought to impede genetic divergence and speciation by homogenizing genomes. Recent theory and research suggest that sufficiently strong divergent selection can overpower gene flow, leading to loci that are highly differentiated compared to others. However, there are also alternative explanations for this pattern. Independent evidence that loci in highly differentiated regions are under divergent selection would allow these explanations to be distinguished, but such evidence is scarce. Here, we present multiple lines of evidence that many of the highly divergent SNPs in a pair of sister morning glory species, Ipomoea cordatotriloba and I. lacunosa, are the result of divergent selection in the face of gene flow. We analysed a SNP data set across the genome to assess the amount of gene flow, resistance to introgression and patterns of selection on loci resistant to introgression. We show that differentiation between the two species is much lower in sympatry than in allopatry, consistent with interspecific gene flow in sympatry. Gene flow appears to be substantially greater from I. lacunosa to I. cordatotriloba than in the reverse direction, resulting in sympatric and allopatric I. cordatotriloba being substantially more different than sympatric and allopatric I. lacunosa. Many SNPs highly differentiated in allopatry have experienced divergent selection, and, despite gene flow in sympatry, resist homogenization in sympatry. Finally, five out of eight floral and inflorescence characteristics measured exhibit asymmetric convergence in sympatry. Consistent with the pattern of gene flow, I. cordatotriloba traits become much more like those of I. lacunosa than the reverse. Our investigation reveals the complex interplay between selection and gene flow that can occur during the early stages of speciation.
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Affiliation(s)
- Joanna L Rifkin
- Department of Biology, Duke University, Durham, North Carolina
| | | | - Irene T Liao
- Department of Biology, Duke University, Durham, North Carolina
| | - Mark D Rausher
- Department of Biology, Duke University, Durham, North Carolina
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16
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Introgression between Anopheles gambiae and Anopheles coluzzii in Burkina Faso and its associations with kdr resistance and Plasmodium infection. Malar J 2019; 18:127. [PMID: 30971230 PMCID: PMC6458625 DOI: 10.1186/s12936-019-2759-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 04/01/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insecticide resistance in Anopheles coluzzii mosquitoes has become widespread throughout West Africa including in Burkina Faso. The insecticide resistance allele (kdr or L1014F) is a prime indicator that is highly correlated with phenotypic resistance in West Africa. Studies from Benin, Ghana and Mali have suggested that the source of the L1014F is introgression of the 2L divergence island via interspecific hybridization with Anopheles gambiae. The goal of this study was to characterize local mosquito populations in the Nouna Department, Burkina Faso with respect to: (i) the extent of introgression between An. coluzzii and An. gambiae, (ii) the frequency of the L1014F mutation and (iii) Plasmodium infection rates. METHODS A total of 95 mosquitoes were collected from ten sites surrounding Nouna town in Kossi Province, Burkina Faso in 2012. The species composition, the extent of introgression in An. coluzzii mosquitoes and their Plasmodium infection rates were identified with a modified version of the "Divergence Island SNP" (DIS) genotyping assay. RESULTS The mosquito collection contained 70.5% An. coluzzii, 89.3% of which carried a 3 Mb genomic region on the 2L chromosome with L1014F insecticide resistance mutation that was introgressed from An. gambiae. In addition, 22.4% in the introgressed An. coluzzii specimens were infected with Plasmodium falciparum, whereas none of the non-introgressed ("pure") An. coluzzii were infected. CONCLUSION This paper is the first report providing divergence island SNP genotypes for natural population of Burkina Faso and corresponding Plasmodium infection rates. These observations warrant further study and could have a major impact on future malaria control strategies in Burkina Faso.
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17
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Hanemaaijer MJ, Collier TC, Chang A, Shott CC, Houston PD, Schmidt H, Main BJ, Cornel AJ, Lee Y, Lanzaro GC. The fate of genes that cross species boundaries after a major hybridization event in a natural mosquito population. Mol Ecol 2018; 27:4978-4990. [DOI: 10.1111/mec.14947] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Mark J. Hanemaaijer
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Travis C. Collier
- Daniel K. Inouye US Pacific Basin Agricultural Research Center (PBARC), United States Department of Agriculture Agricultural Research Service Hilo Hawaii
| | - Allison Chang
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Chloe C. Shott
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Parker D. Houston
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Hanno Schmidt
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Bradley J. Main
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Anthony J. Cornel
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
- Mosquito Control Research Laboratory, Department of Entomology and Nematology University of California Parlier California
- School of Health Systems & Public Health University of Pretoria Pretoria South Africa
| | - Yoosook Lee
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
| | - Gregory C. Lanzaro
- Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology UC Davis Davis California
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18
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Nouhaud P, Gautier M, Gouin A, Jaquiéry J, Peccoud J, Legeai F, Mieuzet L, Smadja CM, Lemaitre C, Vitalis R, Simon JC. Identifying genomic hotspots of differentiation and candidate genes involved in the adaptive divergence of pea aphid host races. Mol Ecol 2018; 27:3287-3300. [PMID: 30010213 DOI: 10.1111/mec.14799] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 01/01/2023]
Abstract
Identifying the genomic bases of adaptation to novel environments is a long-term objective in evolutionary biology. Because genetic differentiation is expected to increase between locally adapted populations at the genes targeted by selection, scanning the genome for elevated levels of differentiation is a first step towards deciphering the genomic architecture underlying adaptive divergence. The pea aphid Acyrthosiphon pisum is a model of choice to address this question, as it forms a large complex of plant-specialized races and cryptic species, resulting from recent adaptive radiation. Here, we characterized genomewide polymorphisms in three pea aphid races specialized on alfalfa, clover and pea crops, respectively, which we sequenced in pools (poolseq). Using a model-based approach that explicitly accounts for selection, we identified 392 genomic hotspots of differentiation spanning 47.3 Mb and 2,484 genes (respectively, 9.12% of the genome size and 8.10% of its genes). Most of these highly differentiated regions were located on the autosomes, and overall differentiation was weaker on the X chromosome. Within these hotspots, high levels of absolute divergence between races suggest that these regions experienced less gene flow than the rest of the genome, most likely by contributing to reproductive isolation. Moreover, population-specific analyses showed evidence of selection in every host race, depending on the hotspot considered. These hotspots were significantly enriched for candidate gene categories that control host-plant selection and use. These genes encode 48 salivary proteins, 14 gustatory receptors, 10 odorant receptors, five P450 cytochromes and one chemosensory protein, which represent promising candidates for the genetic basis of host-plant specialization and ecological isolation in the pea aphid complex. Altogether, our findings open new research directions towards functional studies, for validating the role of these genes on adaptive phenotypes.
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Affiliation(s)
| | - Mathieu Gautier
- CBGP, Univ Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
- Institut de Biologie Computationnelle, Univ Montpellier, Montpellier, France
| | - Anaïs Gouin
- INRA, UMR 1349 IGEPP, Le Rheu, France
- Inria/IRISA GenScale, Rennes, France
| | | | - Jean Peccoud
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
| | - Fabrice Legeai
- INRA, UMR 1349 IGEPP, Le Rheu, France
- Inria/IRISA GenScale, Rennes, France
| | | | - Carole M Smadja
- Institut des Sciences de l'Evolution (UMR 5554) - CNRS - IRD - EPHE - CIRAD -Université de Montpellier, Montpellier, France
| | | | - Renaud Vitalis
- CBGP, Univ Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
- Institut de Biologie Computationnelle, Univ Montpellier, Montpellier, France
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19
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O'Neill MJ, O'Neill RJ. Sex chromosome repeats tip the balance towards speciation. Mol Ecol 2018; 27:3783-3798. [PMID: 29624756 DOI: 10.1111/mec.14577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 03/08/2018] [Accepted: 03/26/2018] [Indexed: 12/11/2022]
Abstract
Because sex chromosomes, by definition, carry genes that determine sex, mutations that alter their structural and functional stability can have immediate consequences for the individual by reducing fertility, but also for a species by altering the sex ratio. Moreover, the sex-specific segregation patterns of heteromorphic sex chromosomes make them havens for selfish genetic elements that not only create suboptimal sex ratios but can also foster sexual antagonism. Compensatory mutations to mitigate antagonism or return sex ratios to a Fisherian optimum can create hybrid incompatibility and establish reproductive barriers leading to species divergence. The destabilizing influence of these selfish elements is often manifest within populations as copy number variants (CNVs) in satellite repeats and transposable elements (TE) or as CNVs involving sex-determining genes, or genes essential to fertility and sex chromosome dosage compensation. This review catalogs several examples of well-studied sex chromosome CNVs in Drosophilids and mammals that underlie instances of meiotic drive, hybrid incompatibility and disruptions to sex differentiation and sex chromosome dosage compensation. While it is difficult to pinpoint a direct cause/effect relationship between these sex chromosome CNVs and speciation, it is easy to see how their effects in creating imbalances between the sexes, and the compensatory mutations to restore balance, can lead to lineage splitting and species formation.
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Affiliation(s)
- Michael J O'Neill
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut
| | - Rachel J O'Neill
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut
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20
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Reeve J, Ortiz-Barrientos D, Engelstädter J. The evolution of recombination rates in finite populations during ecological speciation. Proc Biol Sci 2017; 283:rspb.2016.1243. [PMID: 27798297 DOI: 10.1098/rspb.2016.1243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 10/04/2016] [Indexed: 11/12/2022] Open
Abstract
Recombination can impede ecological speciation with gene flow by mixing locally adapted genotypes with maladapted migrant genotypes from a divergent population. In such a scenario, suppression of recombination can be selectively favoured. However, in finite populations evolving under the influence of random genetic drift, recombination can also facilitate adaptation by reducing Hill-Robertson interference between loci under selection. In this case, increased recombination rates can be favoured. Although these two major effects on recombination have been studied individually, their joint effect on ecological speciation with gene flow remains unexplored. Using a mathematical model, we investigated the evolution of recombination rates in two finite populations that exchange migrants while adapting to contrasting environments. Our results indicate a two-step dynamic where increased recombination is first favoured (in response to the Hill-Robertson effect), and then disfavoured, as the cost of recombining locally with maladapted migrant genotypes increases over time (the maladaptive gene flow effect). In larger populations, a stronger initial benefit for recombination was observed, whereas high migration rates intensify the long-term cost of recombination. These dynamics may have important implications for our understanding of the conditions that facilitate incipient speciation with gene flow and the evolution of recombination in finite populations.
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Affiliation(s)
- James Reeve
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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21
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Schmickl R, Marburger S, Bray S, Yant L. Hybrids and horizontal transfer: introgression allows adaptive allele discovery. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5453-5470. [PMID: 29096001 DOI: 10.1093/jxb/erx297] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Evolution has devised countless remarkable solutions to diverse challenges. Understanding the mechanistic basis of these solutions provides insights into how biological systems can be subtly tweaked without maladaptive consequences. The knowledge gained from illuminating these mechanisms is equally important to our understanding of fundamental evolutionary mechanisms as it is to our hopes of developing truly rational plant breeding and synthetic biology. In particular, modern population genomic approaches are proving very powerful in the detection of candidate alleles for mediating consequential adaptations that can be tested functionally. Especially striking are signals gained from contexts involving genetic transfers between populations, closely related species, or indeed between kingdoms. Here we discuss two major classes of these scenarios, adaptive introgression and horizontal gene flow, illustrating discoveries made across kingdoms.
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Affiliation(s)
- Roswitha Schmickl
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague, Czech Republic
| | - Sarah Marburger
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Sian Bray
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Levi Yant
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
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22
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Burri R. Dissecting differentiation landscapes: a linked selection's perspective. J Evol Biol 2017; 30:1501-1505. [DOI: 10.1111/jeb.13108] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/10/2017] [Accepted: 04/12/2017] [Indexed: 02/01/2023]
Affiliation(s)
- R. Burri
- Department of Population Ecology; Institute of Ecology; Friedrich Schiller University Jena; Jena Germany
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23
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Ragland GJ, Doellman MM, Meyers PJ, Hood GR, Egan SP, Powell THQ, Hahn DA, Nosil P, Feder JL. A test of genomic modularity among life-history adaptations promoting speciation with gene flow. Mol Ecol 2017; 26:3926-3942. [DOI: 10.1111/mec.14178] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Gregory J. Ragland
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
- Environmental Change Initiative; University of Notre Dame; Notre Dame IN USA
- Department of Integrative Biology; University of Colorado - Denver; Denver CO USA
| | | | - Peter J. Meyers
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
| | - Glen R. Hood
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
- Department of Biosciences; Rice University; Houston TX USA
| | - Scott P. Egan
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
- Department of Biosciences; Rice University; Houston TX USA
- Advanced Diagnostics and Therapeutics Initiative; University of Notre Dame; Notre Dame IN USA
| | - Thomas H. Q. Powell
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
- Department of Entomology and Nematology; University of Florida; Gainesville FL USA
- Department of Biological Sciences; State University of New York - Binghamton; Binghamton NY USA
| | - Daniel A. Hahn
- Department of Entomology and Nematology; University of Florida; Gainesville FL USA
| | - Patrik Nosil
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - Jeffrey L. Feder
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN USA
- Environmental Change Initiative; University of Notre Dame; Notre Dame IN USA
- Advanced Diagnostics and Therapeutics Initiative; University of Notre Dame; Notre Dame IN USA
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24
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Vicente JL, Clarkson CS, Caputo B, Gomes B, Pombi M, Sousa CA, Antao T, Dinis J, Bottà G, Mancini E, Petrarca V, Mead D, Drury E, Stalker J, Miles A, Kwiatkowski DP, Donnelly MJ, Rodrigues A, Torre AD, Weetman D, Pinto J. Massive introgression drives species radiation at the range limit of Anopheles gambiae. Sci Rep 2017; 7:46451. [PMID: 28417969 PMCID: PMC5394460 DOI: 10.1038/srep46451] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 03/17/2017] [Indexed: 12/30/2022] Open
Abstract
Impacts of introgressive hybridisation may range from genomic erosion and species collapse to rapid adaptation and speciation but opportunities to study these dynamics are rare. We investigated the extent, causes and consequences of a hybrid zone between Anopheles coluzzii and Anopheles gambiae in Guinea-Bissau, where high hybridisation rates appear to be stable at least since the 1990s. Anopheles gambiae was genetically partitioned into inland and coastal subpopulations, separated by a central region dominated by A. coluzzii. Surprisingly, whole genome sequencing revealed that the coastal region harbours a hybrid form characterised by an A. gambiae-like sex chromosome and massive introgression of A. coluzzii autosomal alleles. Local selection on chromosomal inversions may play a role in this process, suggesting potential for spatiotemporal stability of the coastal hybrid form and providing resilience against introgression of medically-important loci and traits, found to be more prevalent in inland A. gambiae.
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Affiliation(s)
- José L Vicente
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal
| | - Christopher S Clarkson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Beniamino Caputo
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy
| | - Bruno Gomes
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal
| | - Marco Pombi
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy
| | - Carla A Sousa
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal
| | - Tiago Antao
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - João Dinis
- Instituto Nacional de Saúde Pública, Ministério da Saúde Pública, Bissau, Guiné-Bissau
| | - Giordano Bottà
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy.,Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Emiliano Mancini
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy
| | - Vincenzo Petrarca
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy.,Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Biologia e Biotecnologie "Charles Darwin", Università di Roma "Sapienza", Rome, Italy
| | - Daniel Mead
- Wellcome Trust Sanger Institute, Hinxton, UK
| | | | | | - Alistair Miles
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.,Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.,Wellcome Trust Sanger Institute, Hinxton, UK.,Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Amabélia Rodrigues
- Instituto Nacional de Saúde Pública, Ministério da Saúde Pública, Bissau, Guiné-Bissau
| | - Alessandra Della Torre
- Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "Sapienza", Rome, Italy
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - João Pinto
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal
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25
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Van Doren BM, Campagna L, Helm B, Illera JC, Lovette IJ, Liedvogel M. Correlated patterns of genetic diversity and differentiation across an avian family. Mol Ecol 2017; 26:3982-3997. [PMID: 28256062 DOI: 10.1111/mec.14083] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/19/2017] [Accepted: 02/22/2017] [Indexed: 01/01/2023]
Abstract
Comparative studies of closely related taxa can provide insights into the evolutionary forces that shape genome evolution and the prevalence of convergent molecular evolution. We investigated patterns of genetic diversity and differentiation in stonechats (genus Saxicola), a widely distributed avian species complex with phenotypic variation in plumage, morphology and migratory behaviour, to ask whether similar genomic regions have become differentiated in independent, but closely related, taxa. We used whole-genome pooled sequencing of 262 individuals from five taxa and found that levels of genetic diversity and divergence are strongly correlated among different stonechat taxa. We then asked whether these patterns remain correlated at deeper evolutionary scales and found that homologous genomic regions have become differentiated in stonechats and the closely related Ficedula flycatchers. Such correlation across a range of evolutionary divergence and among phylogenetically independent comparisons suggests that similar processes may be driving the differentiation of these independently evolving lineages, which in turn may be the result of intrinsic properties of particular genomic regions (e.g. areas of low recombination). Consequently, studies employing genome scans to search for areas important for reproductive isolation or adaptation should account for corresponding regions of differentiation, as these regions may not necessarily represent speciation islands or evidence of local adaptation.
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Affiliation(s)
- Benjamin M Van Doren
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.,Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | - Leonardo Campagna
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.,Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | - Barbara Helm
- Animal Health and Comparative Medicine, Institute of Biodiversity, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Juan Carlos Illera
- Research Unit of Biodiversity (UO-CSIC-PA), Oviedo University, Campus of Mieres, Research Building, 5th Floor, c/ Gonzalo Gutiérrez Quirós s/n, 33600, Mieres, Asturias, Spain
| | - Irby J Lovette
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.,Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | - Miriam Liedvogel
- Max Planck Institute for Evolutionary Biology, AG Behavioural Genomics, August-Thienemann-Str. 2, 24306, Plön, Germany
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26
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Caputo B, Pichler V, Mancini E, Pombi M, Vicente JL, Dinis J, Steen K, Petrarca V, Rodrigues A, Pinto J, Della Torre A, Weetman D. The last bastion? X chromosome genotyping of Anopheles gambiae species pair males from a hybrid zone reveals complex recombination within the major candidate 'genomic island of speciation'. Mol Ecol 2016; 25:5719-5731. [PMID: 27661465 DOI: 10.1111/mec.13840] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 07/19/2016] [Accepted: 09/01/2016] [Indexed: 01/19/2023]
Abstract
Speciation with gene flow may be aided by reduced recombination helping to build linkage between genes involved in the early stages of reproductive isolation. Reduced recombination on chromosome X has been implicated in speciation within the Anopheles gambiae complex, species of which represent the major Afrotropical malaria vectors. The most recently diverged, morphologically indistinguishable, species pair, A. gambiae and Anopheles coluzzii, ubiquitously displays a 'genomic island of divergence' spanning over 4 Mb from chromosome X centromere, which represents a particularly promising candidate region for reproductive isolation genes, in addition to containing the diagnostic markers used to distinguish the species. Very low recombination makes the island intractable for experimental recombination studies, but an extreme hybrid zone in Guinea Bissau offers the opportunity for natural investigation of X-island recombination. SNP analysis of chromosome X hemizygous males revealed: (i) strong divergence in the X-island despite a lack of autosomal divergence; (ii) individuals with multiple-recombinant genotypes, including likely double crossovers and localized gene conversion; (iii) recombination-driven discontinuity both within and between the molecular species markers, suggesting that the utility of the diagnostics is undermined under high hybridization. The largely, but incompletely protected nature of the X centromeric genomic island is consistent with a primary candidate area for accumulation of adaptive variants driving speciation with gene flow, while permitting some selective shuffling and removal of genetic variation.
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Affiliation(s)
- Beniamino Caputo
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Verena Pichler
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Emiliano Mancini
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Marco Pombi
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - José L Vicente
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua daJunqueira, 100, 1349-008, Lisboa, Portugal
| | - Joao Dinis
- Instituto Nacional de Saúde Pública, Ministério da Saúde Pública, Avenida Combatentes da Liberdade da Pátria, Apartado 861, 1004, Bissau Codex, Guinea Bissau
| | - Keith Steen
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool, Merseyside, L3 5QA, UK
| | - Vincenzo Petrarca
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Biologia e Biotecnologie Charles Darwin, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Amabelia Rodrigues
- Instituto Nacional de Saúde Pública, Ministério da Saúde Pública, Avenida Combatentes da Liberdade da Pátria, Apartado 861, 1004, Bissau Codex, Guinea Bissau
| | - Joao Pinto
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua daJunqueira, 100, 1349-008, Lisboa, Portugal
| | - Alessandra Della Torre
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università 'Sapienza', Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - David Weetman
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool, Merseyside, L3 5QA, UK
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27
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Salgueiro P, Lopes AS, Mendes C, Charlwood JD, Arez AP, Pinto J, Silveira H. Molecular evolution and population genetics of a Gram-negative binding protein gene in the malaria vector Anopheles gambiae (sensu lato). Parasit Vectors 2016; 9:515. [PMID: 27658383 PMCID: PMC5034674 DOI: 10.1186/s13071-016-1800-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/14/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Clarifying the role of the innate immune system of the malaria vector Anopheles gambiae is a potential way to block the development of the Plasmodium parasites. Pathogen recognition is the first step of innate immune response, where pattern recognition proteins like GNBPs play a central role. RESULTS We analysed 70 sequences of the protein coding gene GNBPB2 from two species, Anopheles gambiae (s.s.) and An. coluzzii, collected in six African countries. We detected 135 segregating sites defining 63 distinct haplotypes and 30 proteins. Mean nucleotide diversity (π) was 0.014 for both species. We found no significant genetic differentiation between species, but a significant positive correlation between genetic differentiation and geographical distance among populations. CONCLUSIONS Species status seems to contribute less for the molecular differentiation in GNBPB2 than geographical region in the African continent (West and East). Purifying selection was found to be the most common form of selection, as in many other immunity-related genes. Diversifying selection may be also operating in the GNBPB2 gene.
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Affiliation(s)
- Patrícia Salgueiro
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ana Sofia Lopes
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
| | - Cristina Mendes
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
| | - Jacques Derek Charlwood
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
- London School of Hygiene and Tropical Medicine, London, UK
| | - Ana Paula Arez
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
| | - João Pinto
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
| | - Henrique Silveira
- Global Health and Tropical Medicine Centre (GHTM), Unidade de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Lisboa, Portugal
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28
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Abstract
Anopheles melas is a member of the recently diverged An. gambiae species complex, a model for speciation studies, and is a locally important malaria vector along the West-African coast where it breeds in brackish water. A recent population genetic study of An. melas revealed species-level genetic differentiation between three population clusters. An. melas West extends from The Gambia to the village of Tiko, Cameroon. The other mainland cluster, An. melas South, extends from the southern Cameroonian village of Ipono to Angola. Bioko Island, Equatorial Guinea An. melas populations are genetically isolated from mainland populations. To examine how genetic differentiation between these An. melas forms is distributed across their genomes, we conducted a genome-wide analysis of genetic differentiation and selection using whole genome sequencing data of pooled individuals (Pool-seq) from a representative population of each cluster. The An. melas forms exhibit high levels of genetic differentiation throughout their genomes, including the presence of numerous fixed differences between clusters. Although the level of divergence between the clusters is on a par with that of other species within the An. gambiae complex, patterns of genome-wide divergence and diversity do not provide evidence for the presence of pre- and/or postmating isolating mechanisms in the form of speciation islands. These results are consistent with an allopatric divergence process with little or no introgression.
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29
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Genetic Structure of a Local Population of the Anopheles gambiae Complex in Burkina Faso. PLoS One 2016; 11:e0145308. [PMID: 26731649 PMCID: PMC4701492 DOI: 10.1371/journal.pone.0145308] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/01/2015] [Indexed: 01/21/2023] Open
Abstract
Members of the Anopheles gambiae species complex are primary vectors of human malaria in Africa. Population heterogeneities for ecological and behavioral attributes expand and stabilize malaria transmission over space and time, and populations may change in response to vector control, urbanization and other factors. There is a need for approaches to comprehensively describe the structure and characteristics of a sympatric local mosquito population, because incomplete knowledge of vector population composition may hinder control efforts. To this end, we used a genome-wide custom SNP typing array to analyze a population collection from a single geographic region in West Africa. The combination of sample depth (n = 456) and marker density (n = 1536) unambiguously resolved population subgroups, which were also compared for their relative susceptibility to natural genotypes of Plasmodium falciparum malaria. The population subgroups display fluctuating patterns of differentiation or sharing across the genome. Analysis of linkage disequilibrium identified 19 new candidate genes for association with underlying population divergence between sister taxa, A. coluzzii (M-form) and A. gambiae (S-form).
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30
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Mitri C, Bischoff E, Takashima E, Williams M, Eiglmeier K, Pain A, Guelbeogo WM, Gneme A, Brito-Fravallo E, Holm I, Lavazec C, Sagnon N, Baxter RH, Riehle MM, Vernick KD. An Evolution-Based Screen for Genetic Differentiation between Anopheles Sister Taxa Enriches for Detection of Functional Immune Factors. PLoS Pathog 2015; 11:e1005306. [PMID: 26633695 PMCID: PMC4669117 DOI: 10.1371/journal.ppat.1005306] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/03/2015] [Indexed: 11/26/2022] Open
Abstract
Nucleotide variation patterns across species are shaped by the processes of natural selection, including exposure to environmental pathogens. We examined patterns of genetic variation in two sister species, Anopheles gambiae and Anopheles coluzzii, both efficient natural vectors of human malaria in West Africa. We used the differentiation signature displayed by a known coordinate selective sweep of immune genes APL1 and TEP1 in A. coluzzii to design a population genetic screen trained on the sweep, classified a panel of 26 potential immune genes for concordance with the signature, and functionally tested their immune phenotypes. The screen results were strongly predictive for genes with protective immune phenotypes: genes meeting the screen criteria were significantly more likely to display a functional phenotype against malaria infection than genes not meeting the criteria (p = 0.0005). Thus, an evolution-based screen can efficiently prioritize candidate genes for labor-intensive downstream functional testing, and safely allow the elimination of genes not meeting the screen criteria. The suite of immune genes with characteristics similar to the APL1-TEP1 selective sweep appears to be more widespread in the A. coluzzii genome than previously recognized. The immune gene differentiation may be a consequence of adaptation of A. coluzzii to new pathogens encountered in its niche expansion during the separation from A. gambiae, although the role, if any of natural selection by Plasmodium is unknown. Application of the screen allowed identification of new functional immune factors, and assignment of new functions to known factors. We describe biochemical binding interactions between immune proteins that underlie functional activity for malaria infection, which highlights the interplay between pathogen specificity and the structure of immune complexes. We also find that most malaria-protective immune factors display phenotypes for either human or rodent malaria, with broad specificity a rarity. Anopheles gambiae and Anopheles coluzzii are the primary mosquito vectors of human malaria in West Africa. Both of these closely related species efficiently transmit the disease, although they display ecological differences. Previous work showed that A. coluzzii displays distinct genetic patterns in genes important for mosquito immunity. Here, we use this genetic pattern as a filter to examine a panel of potential immune genes, and show that the genetic pattern is strongly predictive for genes that play a functional role in immunity when tested with malaria parasites.
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Affiliation(s)
- Christian Mitri
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Emmanuel Bischoff
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Eizo Takashima
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Marni Williams
- Department of Chemistry and Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Karin Eiglmeier
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Adrien Pain
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | | | - Awa Gneme
- Centre National de Recherche et de Formation sur le Paludisme, Burkina Faso
| | - Emma Brito-Fravallo
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Inge Holm
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Catherine Lavazec
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - N’Fale Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, Burkina Faso
| | - Richard H. Baxter
- Department of Chemistry and Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Michelle M. Riehle
- Department of Microbiology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Kenneth D. Vernick
- Institut Pasteur, Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Paris, France
- CNRS, Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
- Department of Microbiology, University of Minnesota, Saint Paul, Minnesota, United States of America
- * E-mail:
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31
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Niang A, Epopa PS, Sawadogo SP, Maïga H, Konaté L, Faye O, Dabiré RK, Tripet F, Diabaté A. Does extreme asymmetric dominance promote hybridization between Anopheles coluzzii and Anopheles gambiae s.s. in seasonal malaria mosquito communities of West Africa? Parasit Vectors 2015; 8:586. [PMID: 26559354 PMCID: PMC4642620 DOI: 10.1186/s13071-015-1190-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/31/2015] [Indexed: 03/13/2023] Open
Abstract
Background Anopheles gambiae s.s. and An. coluzzii are two of the most important malaria vector species in sub-Saharan Africa. These recently-diverged sibling species do not exhibit intrinsic post-zygotic barriers to reproduction and are thought to be separated by strong assortative mating combined with selection against hybrids. At present, little is known about the ecological conditions that determine hybridization and introgression between these cryptic taxa. Methods Swarm segregation and assortative mating were studied in Western Burkina Faso in the villages of Vallée du Kou (VK7) and Soumousso which differed in terms of which sibling species was much rarer than the other, and in Bana where both occurred in similar proportions. Swarms and pairs in copula were collected and genotyped, the proportion of intra and interspecific mating determined, and interspecific sperm transfer checked genetically. Females were collected through larval and adult indoor collections and genotyped or sexed-and-genotyped via a novel multiplex PCR. Results A total of 3,687 males and 220 females were collected and genotyped from 109 swarms. Only 3 swarms were composed of males from both species, and these were from the village of VK7 where An. gambiae s.s. was comparatively rare. Mixed-species pairs captured in copula were only detected in that area and made for 3.62 % and 100 % of mating pairs involving An. coluzzii and An. gambiae s.s. individuals, respectively. The high An. gambiae s.s. cross-mating rate was mirrored by high rates of hybridizations estimated from female larvae and adults indoor collections. This contrasted with Soumousso, where despite being much less common than An. gambiae s.s., An. coluzzii males did not form mixed swarms, females were not found in interspecific swarms or copula and hybridization rates were low in both sibling species. Conclusions These data suggest that ecological conditions leading to rare An. gambiae s.s. in populations dominated by An. coluzzii may promote a breakdown of spatial swarm segregation and assortative mating between the two species. The lower overall hybridization rates observed at the larval and adult indoor stages compared to cross-mating rates support the idea that post-mating selection processes acting against hybrids may occur mostly prior to and/or at the early larval stages.
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Affiliation(s)
- Abdoulaye Niang
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Patric S Epopa
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Simon P Sawadogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Hamidou Maïga
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Lassana Konaté
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal.
| | - Ousmane Faye
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal.
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Frédéric Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK.
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
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32
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Main BJ, Lee Y, Collier TC, Norris LC, Brisco K, Fofana A, Cornel AJ, Lanzaro GC. Complex genome evolution in Anopheles coluzzii associated with increased insecticide usage in Mali. Mol Ecol 2015; 24:5145-57. [PMID: 26359110 PMCID: PMC4615556 DOI: 10.1111/mec.13382] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 08/07/2015] [Accepted: 08/21/2015] [Indexed: 01/01/2023]
Abstract
In certain cases, a species may have access to important genetic variation present in a related species via adaptive introgression. These novel alleles may interact with their new genetic background, resulting in unexpected phenotypes. In this study, we describe a selective sweep on standing variation on the X chromosome in the mosquito Anopheles coluzzii, a principal malaria vector in West Africa. This event may have been influenced by the recent adaptive introgression of the insecticide resistance gene known as kdr from the sister species Anopheles gambiae. Individuals carrying both kdr and a nearly fixed X-linked haplotype, encompassing at least four genes including the P450 gene CYP9K1 and the cuticular protein CPR125, have rapidly increased in relative frequency. In parallel, a reproductively isolated insecticide-susceptible A. gambiae population (Bamako form) has been driven to local extinction, likely due to strong selection from increased insecticide-treated bed net usage.
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Affiliation(s)
- Bradley J Main
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Pathology, Microbiology and Immunology, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA
| | - Yoosook Lee
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Pathology, Microbiology and Immunology, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA
| | - Travis C Collier
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Pathology, Microbiology and Immunology, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA
| | - Laura C Norris
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Pathology, Microbiology and Immunology, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA
| | - Katherine Brisco
- Department of Entomology and Nematology, University of California, Davis, CA, 95616, USA
| | - Abdrahamane Fofana
- Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali
| | - Anthony J Cornel
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Entomology and Nematology, University of California, Davis, CA, 95616, USA
| | - Gregory C Lanzaro
- Vector Genetics Laboratory, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA.,Department of Pathology, Microbiology and Immunology, UC Davis, 1089 Veterinary Medicine Dr, 4225 VM3B, Davis, CA, 95616, USA
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Burri R, Nater A, Kawakami T, Mugal CF, Olason PI, Smeds L, Suh A, Dutoit L, Bureš S, Garamszegi LZ, Hogner S, Moreno J, Qvarnström A, Ružić M, Sæther SA, Sætre GP, Török J, Ellegren H. Linked selection and recombination rate variation drive the evolution of the genomic landscape of differentiation across the speciation continuum of Ficedula flycatchers. Genome Res 2015; 25:1656-65. [PMID: 26355005 PMCID: PMC4617962 DOI: 10.1101/gr.196485.115] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/30/2015] [Indexed: 12/19/2022]
Abstract
Speciation is a continuous process during which genetic changes gradually accumulate in the genomes of diverging species. Recent studies have documented highly heterogeneous differentiation landscapes, with distinct regions of elevated differentiation (“differentiation islands”) widespread across genomes. However, it remains unclear which processes drive the evolution of differentiation islands; how the differentiation landscape evolves as speciation advances; and ultimately, how differentiation islands are related to speciation. Here, we addressed these questions based on population genetic analyses of 200 resequenced genomes from 10 populations of four Ficedula flycatcher sister species. We show that a heterogeneous differentiation landscape starts emerging among populations within species, and differentiation islands evolve recurrently in the very same genomic regions among independent lineages. Contrary to expectations from models that interpret differentiation islands as genomic regions involved in reproductive isolation that are shielded from gene flow, patterns of sequence divergence (dxy and relative node depth) do not support a major role of gene flow in the evolution of the differentiation landscape in these species. Instead, as predicted by models of linked selection, genome-wide variation in diversity and differentiation can be explained by variation in recombination rate and the density of targets for selection. We thus conclude that the heterogeneous landscape of differentiation in Ficedula flycatchers evolves mainly as the result of background selection and selective sweeps in genomic regions of low recombination. Our results emphasize the necessity of incorporating linked selection as a null model to identify genome regions involved in adaptation and speciation.
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Affiliation(s)
- Reto Burri
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Alexander Nater
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Takeshi Kawakami
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Carina F Mugal
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Pall I Olason
- Wallenberg Advanced Bioinformatics Infrastructure (WABI), Science for Life Laboratory, Uppsala University, 75123 Uppsala, Sweden
| | - Linnea Smeds
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Alexander Suh
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Ludovic Dutoit
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Stanislav Bureš
- Laboratory of Ornithology, Department of Zoology, Palacky University, 77146 Olomouc, Czech Republic
| | - Laszlo Z Garamszegi
- Department of Evolutionary Ecology, Estación Biológica de Doñana-CSIC, 41092 Seville, Spain
| | - Silje Hogner
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway; Natural History Museum, University of Oslo, 0318 Oslo, Norway
| | - Juan Moreno
- Museo Nacional de Ciencias Naturales-CSIC, 28006 Madrid, Spain
| | - Anna Qvarnström
- Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Milan Ružić
- Bird Protection and Study Society of Serbia, Radnička 20a, 21000 Novi Sad, Serbia
| | - Stein-Are Sæther
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway; Norwegian Institute for Nature Research (NINA), 7034 Trondheim, Norway
| | - Glenn-Peter Sætre
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway
| | - Janos Török
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, 1117 Budapest, Hungary
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
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Adaptive Potential of Hybridization among Malaria Vectors: Introgression at the Immune Locus TEP1 between Anopheles coluzzii and A. gambiae in 'Far-West' Africa. PLoS One 2015; 10:e0127804. [PMID: 26047479 PMCID: PMC4457524 DOI: 10.1371/journal.pone.0127804] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/19/2015] [Indexed: 02/02/2023] Open
Abstract
“Far-West” Africa is known to be a secondary contact zone between the two major malaria vectors Anopheles coluzzii and A. gambiae. We investigated gene-flow and potentially adaptive introgression between these species along a west-to-east transect in Guinea Bissau, the putative core of this hybrid zone. To evaluate the extent and direction of gene flow, we genotyped site 702 in Intron-1 of the para Voltage-Gated Sodium Channel gene, a species-diagnostic nucleotide position throughout most of A. coluzzii and A. gambiae sympatric range. We also analyzed polymorphism in the thioester-binding domain (TED) of the innate immunity-linked thioester-containing protein 1 (TEP1) to investigate whether elevated hybridization might facilitate the exchange of variants linked to adaptive immunity and Plasmodium refractoriness. Our results confirm asymmetric introgression of genetic material from A. coluzzii to A. gambiae and disruption of linkage between the centromeric "genomic islands" of inter-specific divergence. We report that A. gambiae from the Guinean hybrid zone possesses an introgressed TEP1 resistant allelic class, found exclusively in A. coluzzii elsewhere and apparently swept to fixation in West Africa (i.e. Mali and Burkina Faso). However, no detectable fixation of this allele was found in Guinea Bissau, which may suggest that ecological pressures driving segregation between the two species in larval habitats in this region may be different from those experienced in northern and more arid parts of the species’ range. Finally, our results also suggest a genetic subdivision between coastal and inland A. gambiae Guinean populations and provide clues on the importance of ecological factors in intra-specific differentiation processes.
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Experimental swap of Anopheles gambiae's assortative mating preferences demonstrates key role of X-chromosome divergence island in incipient sympatric speciation. PLoS Genet 2015; 11:e1005141. [PMID: 25880677 PMCID: PMC4400153 DOI: 10.1371/journal.pgen.1005141] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 03/11/2015] [Indexed: 12/12/2022] Open
Abstract
Although many theoretical models of sympatric speciation propose that genes responsible for assortative mating amongst incipient species should be associated with genomic regions protected from recombination, there are few data to support this theory. The malaria mosquito, Anopheles gambiae, is known for its sympatric cryptic species maintained by pre-mating reproductive isolation and its putative genomic islands of speciation, and is therefore an ideal model system for studying the genomic signature associated with incipient sympatric speciation. Here we selectively introgressed the island of divergence located in the pericentric region of the X chromosome of An. gambiae s.s. into its sister taxon An. coluzzii through 5 generations of backcrossing followed by two generations of crosses within the introgressed strains that resulted in An. coluzzii-like recombinant strains fixed for the M and S marker in the X chromosome island. The mating preference of recombinant strains was then tested by giving virgin recombinant individuals a choice of mates with X-islands matching and non-matching their own island type. We show through genetic analyses of transferred sperm that recombinant females consistently mated with matching island-type males thereby associating assortative mating genes with the X-island of divergence. Furthermore, full-genome sequencing confirmed that protein-coding differences between recombinant strains were limited to the experimentally swapped pericentromeric region. Finally, targeted-genome comparisons showed that a number of these unique differences were conserved in sympatric field populations, thereby revealing candidate speciation genes. The functional demonstration of a close association between speciation genes and the X-island of differentiation lends unprecedented support to island-of-speciation models of sympatric speciation facilitated by pericentric recombination suppression. Anopheles gambiae is the most important vector of malaria in Africa. This species is undergoing speciation and a number of subpopulations have been identified which can produce viable hybrid offspring but are reproductively isolated through assortative mating and ecological adaptation. This complex structure provides an ideal system for studying the unique genetic and behavioural processes required for speciation. Anopheles gambiae’s subpopulations differ genetically in limited regions of their genomes called islands of speciation. Theoretical studies predict that these islands, characterized by restricted genetic rearrangements, may protect genes of assortative mating between emerging species, and are fundamental to the speciation process. We set out to test this prediction by performing complex genetic crosses between the sister species Anopheles coluzzii and Anopheles gambiae s.s. and creating recombinant strains differing only at their X-chromosome island of speciation. We show through behavioural studies that recombinant females consistently mated with matching island-type males thereby associating assortative mating genes with the X-island of divergence. By sequencing the genetic code of the recombinant strains and natural populations, we could confirm these findings and identify candidate assortative mating genes. These findings suggest an important role of divergence islands for the genetic and behavioural processes associated with speciation.
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Lee Y, Weakley AM, Nieman CC, Malvick J, Lanzaro GC. A multi-detection assay for malaria transmitting mosquitoes. J Vis Exp 2015:e52385. [PMID: 25867057 DOI: 10.3791/52385] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The Anopheles gambiae species complex includes the major malaria transmitting mosquitoes in Africa. Because these species are of such medical importance, several traits are typically characterized using molecular assays to aid in epidemiological studies. These traits include species identification, insecticide resistance, parasite infection status, and host preference. Since populations of the Anopheles gambiae complex are morphologically indistinguishable, a polymerase chain reaction (PCR) is traditionally used to identify species. Once the species is known, several downstream assays are routinely performed to elucidate further characteristics. For instance, mutations known as KDR in a para gene confer resistance against DDT and pyrethroid insecticides. Additionally, enzyme-linked immunosorbent assays (ELISAs) or Plasmodium parasite DNA detection PCR assays are used to detect parasites present in mosquito tissues. Lastly, a combination of PCR and restriction enzyme digests can be used to elucidate host preference (e.g., human vs. animal blood) by screening the mosquito bloodmeal for host-specific DNA. We have developed a multi-detection assay (MDA) that combines all of the aforementioned assays into a single multiplex reaction genotyping 33SNPs for 96 or 384 samples at a time. Because the MDA includes multiple markers for species, Plasmodium detection, and host blood identification, the likelihood of generating false positives or negatives is greatly reduced from previous assays that include only one marker per trait. This robust and simple assay can detect these key mosquito traits cost-effectively and in a fraction of the time of existing assays.
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Affiliation(s)
- Yoosook Lee
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California - Davis;
| | - Allison M Weakley
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California - Davis
| | - Catelyn C Nieman
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California - Davis
| | - Julia Malvick
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis
| | - Gregory C Lanzaro
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California - Davis
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Feulner PGD, Chain FJJ, Panchal M, Huang Y, Eizaguirre C, Kalbe M, Lenz TL, Samonte IE, Stoll M, Bornberg-Bauer E, Reusch TBH, Milinski M. Genomics of divergence along a continuum of parapatric population differentiation. PLoS Genet 2015; 11:e1004966. [PMID: 25679225 PMCID: PMC4334544 DOI: 10.1371/journal.pgen.1004966] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/19/2014] [Indexed: 12/20/2022] Open
Abstract
The patterns of genomic divergence during ecological speciation are shaped by a combination of evolutionary forces. Processes such as genetic drift, local reduction of gene flow around genes causing reproductive isolation, hitchhiking around selected variants, variation in recombination and mutation rates are all factors that can contribute to the heterogeneity of genomic divergence. On the basis of 60 fully sequenced three-spined stickleback genomes, we explore these different mechanisms explaining the heterogeneity of genomic divergence across five parapatric lake and river population pairs varying in their degree of genetic differentiation. We find that divergent regions of the genome are mostly specific for each population pair, while their size and abundance are not correlated with the extent of genome-wide population differentiation. In each pair-wise comparison, an analysis of allele frequency spectra reveals that 25–55% of the divergent regions are consistent with a local restriction of gene flow. Another large proportion of divergent regions (38–75%) appears to be mainly shaped by hitchhiking effects around positively selected variants. We provide empirical evidence that alternative mechanisms determining the evolution of genomic patterns of divergence are not mutually exclusive, but rather act in concert to shape the genome during population differentiation, a first necessary step towards ecological speciation. A variety of evolutionary forces influence the genomic landscape of divergence during ecological speciation. Here we characterize the evolution of genomic divergence patterns based on 60 fully sequenced three-spined stickleback genomes, contrasting lake and river populations that differ in parasite abundance. Our comparison of the size and abundance of divergent regions in the genomes across a continuum of population differentiation suggests that selection and the hitchhiking effect on neutral sites mainly contributes to the observed heterogeneous patterns of genomic divergence. Additional divergent regions of the genome can be explained by a local reduction of gene flow. Our description of genomic divergence patterns across a continuum of population differentiation combined with an analysis of molecular signatures of evolution highlights how adaptation shapes the differentiation of sticklebacks in freshwater habitats.
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Affiliation(s)
- Philine G. D. Feulner
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Institute for Evolution and Biodiversity, Evolutionary Bioinformatics, Westfälische Wilhelms University, Münster, Germany
- * E-mail:
| | - Frédéric J. J. Chain
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Mahesh Panchal
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Yun Huang
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Christophe Eizaguirre
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Martin Kalbe
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Tobias L. Lenz
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Irene E. Samonte
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Monika Stoll
- Genetic Epidemiology, Westfälische Wilhelms University, Münster, Germany
| | - Erich Bornberg-Bauer
- Institute for Evolution and Biodiversity, Evolutionary Bioinformatics, Westfälische Wilhelms University, Münster, Germany
| | - Thorsten B. H. Reusch
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Manfred Milinski
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
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Santolamazza F, Caputo B, Nwakanma DC, Fanello C, Petrarca V, Conway DJ, Weetman D, Pinto J, Mancini E, della Torre A. Remarkable diversity of intron-1 of the para voltage-gated sodium channel gene in an Anopheles gambiae/Anopheles coluzzii hybrid zone. Malar J 2015; 14:9. [PMID: 25604888 PMCID: PMC4308935 DOI: 10.1186/s12936-014-0522-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/20/2014] [Indexed: 11/26/2022] Open
Abstract
Background Genomic differentiation between Anopheles gambiae and Anopheles coluzzii - the major malaria vectors in sub-Saharan Africa - is localized into large “islands” toward the centromeres of chromosome-X and the two autosomes. Linkage disequilibrium between these genomic islands was first detected between species-specific polymorphisms within ribosomal DNA genes (IGS-rDNA) on the X-chromosome and a single variant at position 702 of intron 1 (Int-1702) of the para Voltage-Gated Sodium Channel (VGSC) gene on chromosome arm 2 L. Intron-1 sequence data from West and Central Africa revealed two clearly distinct and species-specific haplogroups, each characterized by very low polymorphism, which has been attributed to a selective sweep. The aim of this study was to analyse Int-1 sequence diversity in A. gambiae and A. coluzzii populations from the Far-West of their range, in order to assess whether this selective-sweep signature could persist in a zone of high interspecific hybridization. Methods A 531 bp region of VGSC Int-1 was sequenced in 21 A. coluzzii, 31 A. gambiae, and 12 hybrids from The Gambia and Guinea Bissau, located within the Far-West geographical region, and in 53 A. gambiae s.l. samples from the rest of the range. Results Far-West samples exhibit dramatic Int-1 polymorphism, far higher within each country than observed throughout the rest of the species range. Moreover, patterning of haplotypes within A. coluzzii confirms previous evidence of a macro-geographic subdivision into a West and a Central African genetic cluster, and reveals a possible genetic distinction of A. coluzzii populations from the Far-West. Conclusions The results suggest a relaxation of selective pressures acting across the VGSC gene region in the hybrid zone. Genetic differentiation in the Far-West could be attributable to a founder effect within A. coluzzii, with subsequent extensive gene flow with secondarily-colonizing A. gambiae, potentially yielding a novel insight on the dynamic processes impacting genetic divergence of these key malaria vectors. Electronic supplementary material The online version of this article (doi:10.1186/s12936-014-0522-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Emiliano Mancini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "Sapienza", Piazzale Aldo Moro 5, Rome, 00185, Italy.
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Adaptive introgression in an African malaria mosquito coincident with the increased usage of insecticide-treated bed nets. Proc Natl Acad Sci U S A 2015; 112:815-20. [PMID: 25561525 DOI: 10.1073/pnas.1418892112] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animal species adapt to changes in their environment, including man-made changes such as the introduction of insecticides, through selection for advantageous genes already present in populations or newly arisen through mutation. A possible alternative mechanism is the acquisition of adaptive genes from related species via a process known as adaptive introgression. Differing levels of insecticide resistance between two African malaria vectors, Anopheles coluzzii and Anopheles gambiae, have been attributed to assortative mating between the two species. In a previous study, we reported two bouts of hybridization observed in the town of Selinkenyi, Mali in 2002 and 2006. These hybridization events did not appear to be directly associated with insecticide-resistance genes. We demonstrate that during a brief breakdown in assortative mating in 2006, A. coluzzii inherited the entire A. gambiae-associated 2L divergence island, which includes a suite of insecticide-resistance alleles. In this case, introgression was coincident with the start of a major insecticide-treated bed net distribution campaign in Mali. This suggests that insecticide exposure altered the fitness landscape, favoring the survival of A. coluzzii/A. gambiae hybrids, and provided selection pressure that swept the 2L divergence island through A. coluzzii populations in Mali. We propose that the work described herein presents a unique description of the temporal dynamics of adaptive introgression in an animal species and represents a mechanism for the rapid evolution of insecticide resistance in this important vector of human malaria in Africa.
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40
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Feliciello I, Akrap I, Brajković J, Zlatar I, Ugarković Đ. Satellite DNA as a driver of population divergence in the red flour beetle Tribolium castaneum. Genome Biol Evol 2014; 7:228-39. [PMID: 25527837 PMCID: PMC4316633 DOI: 10.1093/gbe/evu280] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tandemly repeated satellite DNAs are among most rapidly evolving sequences in eukaryotic genome, usually differing significantly among closely related species. By inducing changes in heterochromatin and/or centromere, satellite DNAs are expected to drive population and species divergence. However, despite high evolutionary dynamics, divergence of satellite DNA profiles at the level of natural population which precedes and possibly triggers speciation process is not readily detected. Here, we characterize minor TCAST2 satellite DNA of the red flour beetle Tribolium castaneum and follow its dynamics among wild-type strains originating from diverse geographic locations. The investigation revealed presence of three distinct subfamilies of TCAST2 satellite DNA which differ in monomer size, genome organization, and subfamily specific mutations. Subfamilies Tcast2a and Tcast2b are tandemly arranged within pericentromeric heterochromatin whereas Tcast2c is preferentially dispersed within euchromatin of all chromosomes. Among strains, TCAST2 subfamilies are conserved in sequence but exhibit a significant content variability. This results in overrepresentation or almost complete absence of particular subfamily in some strains and enables discrimination between strains. It is proposed that homologous recombination, probably stimulated by environmental stress, is responsible for the emergence of TCAST2 satellite subfamilies, their copy number variation and dispersion within genome. The results represent the first evidence for the existence of population-specific satellite DNA profiles. Partial organization of TCAST2 satellite DNA in the form of single repeats dispersed within euchromatin additionally contributes to the genome divergence at the population level.
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Affiliation(s)
- Isidoro Feliciello
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia Laboratory of Experimental Biology, Department of Clinical Medicine and Surgery, University of Naples Federico II, Italy
| | - Ivana Akrap
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Josip Brajković
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ivo Zlatar
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Đurđica Ugarković
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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41
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A linkage disequilibrium perspective on the genetic mosaic of speciation in two hybridizing Mediterranean white oaks. Heredity (Edinb) 2014; 114:373-86. [PMID: 25515016 DOI: 10.1038/hdy.2014.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 10/11/2014] [Accepted: 11/12/2014] [Indexed: 01/09/2023] Open
Abstract
We analyzed the genetic mosaic of speciation in two hybridizing Mediterranean white oaks from the Iberian Peninsula (Quercus faginea Lamb. and Quercus pyrenaica Willd.). The two species show ecological divergence in flowering phenology, leaf morphology and composition, and in their basic or acidic soil preferences. Ninety expressed sequence tag-simple sequence repeats (EST-SSRs) and eight nuclear SSRs were genotyped in 96 trees from each species. Genotyping was designed in two steps. First, we used 69 markers evenly distributed over the 12 linkage groups (LGs) of the oak linkage map to confirm the species genetic identity of the sampled genotypes, and searched for differentiation outliers. Then, we genotyped 29 additional markers from the chromosome bins containing the outliers and repeated the multilocus scans. We found one or two additional outliers within four saturated bins, thus confirming that outliers are organized into clusters. Linkage disequilibrium (LD) was extensive; even for loosely linked and for independent markers. Consequently, score tests for association between two-marker haplotypes and the 'species trait' showed a broad genomic divergence, although substantial variation across the genome and within LGs was also observed. We discuss the influence of several confounding effects on neutrality tests and review the evolutionary processes leading to extensive LD. Finally, we examine how LD analyses within regions that contain outlier clusters and quantitative trait loci can help to identify regions of divergence and/or genomic hitchhiking in the light of predictions from ecological speciation theory.
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42
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Turissini DA, Gamez S, White BJ. Genome-wide patterns of polymorphism in an inbred line of the African malaria mosquito Anopheles gambiae. Genome Biol Evol 2014; 6:3094-104. [PMID: 25377942 PMCID: PMC4255774 DOI: 10.1093/gbe/evu243] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2014] [Indexed: 12/21/2022] Open
Abstract
Anopheles gambiae is a major mosquito vector of malaria in Africa. Although increased use of insecticide-based vector control tools has decreased malaria transmission, elimination is likely to require novel genetic control strategies. It can be argued that the absence of an A. gambiae inbred line has slowed progress toward genetic vector control. In order to empower genetic studies and enable precise and reproducible experimentation, we set out to create an inbred line of this species. We found that amenability to inbreeding varied between populations of A. gambiae. After full-sib inbreeding for ten generations, we genotyped 112 individuals--56 saved prior to inbreeding and 56 collected after inbreeding--at a genome-wide panel of single nucleotide polymorphisms (SNPs). Although inbreeding dramatically reduced diversity across much of the genome, we discovered numerous, discrete genomic blocks that maintained high heterozygosity. For one large genomic region, we were able to definitively show that high diversity is due to the persistent polymorphism of a chromosomal inversion. Inbred lines in other eukaryotes often exhibit a qualitatively similar retention of polymorphism when typed at a small number of markers. Our whole-genome SNP data provide the first strong, empirical evidence supporting associative overdominance as the mechanism maintaining higher than expected diversity in inbred lines. Although creation of A. gambiae lines devoid of nearly all polymorphism may not be feasible, our results provide critical insights into how more fully isogenic lines can be created.
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Affiliation(s)
| | - Stephanie Gamez
- Department of Entomology, University of California, Riverside
| | - Bradley J White
- Department of Entomology, University of California, Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside
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43
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Long distance linkage disequilibrium and limited hybridization suggest cryptic speciation in atlantic cod. PLoS One 2014; 9:e106380. [PMID: 25259573 PMCID: PMC4178228 DOI: 10.1371/journal.pone.0106380] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 08/06/2014] [Indexed: 11/19/2022] Open
Abstract
Hybrid zones provide unprecedented opportunity for the study of the evolution of reproductive isolation, and the extent of hybridization across individuals and genomes can illuminate the degree of isolation. We examine patterns of interchromosomal linkage disequilibrium (ILD) and the presence of hybridization in Atlantic cod, Gadus morhua, in previously identified hybrid zones in the North Atlantic. Here, previously identified clinal loci were mapped to the cod genome with most (∼70%) occurring in or associated with (<5 kb) coding regions representing a diverse array of possible functions and pathways. Despite the observation that clinal loci were distributed across three linkage groups, elevated ILD was observed among all groups of clinal loci and strongest in comparisons involving a region of low recombination along linkage group 7. Evidence of ILD supports a hypothesis of divergence hitchhiking transitioning to genome hitchhiking consistent with reproductive isolation. This hypothesis is supported by Bayesian characterization of hybrid classes present and we find evidence of common F1 hybrids in several regions consistent with frequent interbreeding, yet little evidence of F2 or backcrossed individuals. This work suggests that significant barriers to hybridization and introgression exist among these co-occurring groups of cod either through strong selection against hybrid individuals, or genetic incompatibility and intrinsic barriers to hybridization. In either case, the presence of strong clinal trends, and little gene flow despite extensive hybridization supports a hypothesis of reproductive isolation and cryptic speciation in Atlantic cod. Further work is required to test the degree and nature of reproductive isolation in this species.
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44
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Feder JL, Nosil P, Flaxman SM. Assessing when chromosomal rearrangements affect the dynamics of speciation: implications from computer simulations. Front Genet 2014; 5:295. [PMID: 25206365 PMCID: PMC4144205 DOI: 10.3389/fgene.2014.00295] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/08/2014] [Indexed: 12/03/2022] Open
Abstract
Many hypotheses have been put forth to explain the origin and spread of inversions, and their significance for speciation. Several recent genic models have proposed that inversions promote speciation with gene flow due to the adaptive significance of the genes contained within them and because of the effects inversions have on suppressing recombination. However, the consequences of inversions for the dynamics of genome wide divergence across the speciation continuum remain unclear, an issue we examine here. We review a framework for the genomics of speciation involving the congealing of the genome into alternate adaptive states representing species (“genome wide congealing”). We then place inversions in this context as examples of how genetic hitchhiking can potentially hasten genome wide congealing. Specifically, we use simulation models to (i) examine the conditions under which inversions may speed genome congealing and (ii) quantify predicted magnitudes of these effects. Effects of inversions on promoting speciation were most common and pronounced when inversions were initially fixed between populations before secondary contact and adaptation involved many genes with small fitness effects. Further work is required on the role of underdominance and epistasis between a few loci of major effect within inversions. The results highlight five important aspects of the roles of inversions in speciation: (i) the geographic context of the origins and spread of inversions, (ii) the conditions under which inversions can facilitate divergence, (iii) the magnitude of that facilitation, (iv) the extent to which the buildup of divergence is likely to be biased within vs. outside of inversions, and (v) the dynamics of the appearance and disappearance of exceptional divergence within inversions. We conclude by discussing the empirical challenges in showing that inversions play a central role in facilitating speciation with gene flow.
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Affiliation(s)
- Jeffrey L Feder
- Department of Biological Sciences, University of Notre Dame Notre Dame, IN, USA
| | - Patrik Nosil
- Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK
| | - Samuel M Flaxman
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO, USA
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Harrison RG, Larson EL. Hybridization, Introgression, and the Nature of Species Boundaries. J Hered 2014; 105 Suppl 1:795-809. [DOI: 10.1093/jhered/esu033] [Citation(s) in RCA: 418] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Clarkson CS, Weetman D, Essandoh J, Yawson AE, Maslen G, Manske M, Field SG, Webster M, Antão T, MacInnis B, Kwiatkowski D, Donnelly MJ. Adaptive introgression between Anopheles sibling species eliminates a major genomic island but not reproductive isolation. Nat Commun 2014; 5:4248. [PMID: 24963649 PMCID: PMC4086683 DOI: 10.1038/ncomms5248] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 05/28/2014] [Indexed: 11/16/2022] Open
Abstract
Adaptive introgression can provide novel genetic variation to fuel rapid evolutionary
responses, though it may be counterbalanced by potential for detrimental disruption of the
recipient genomic background. We examine the extent and impact of recent introgression of a
strongly selected insecticide-resistance mutation (Vgsc-1014F) located within one of
two exceptionally large genomic islands of divergence separating the Anopheles
gambiae species pair. Here we show that transfer of the Vgsc mutation results
in homogenization of the entire genomic island region (~1.5% of the genome) between
species. Despite this massive disruption, introgression is clearly adaptive with a dramatic
rise in frequency of Vgsc-1014F and no discernable impact on subsequent reproductive
isolation between species. Our results show (1) how resilience of genomes to massive
introgression can permit rapid adaptive response to anthropogenic selection and (2) that
even extreme prominence of genomic islands of divergence can be an unreliable indicator of
importance in speciation. Highly divergent genomic islands segregate between a species pair of the
mosquito, Anopheles gambiae. Here Clarkson et al. show that loss of one of the
largest islands, driven by adaptive introgression of an insecticide-resistance mutation, had
no impact on reproductive isolation.
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Affiliation(s)
- Chris S Clarkson
- 1] Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK [2]
| | - David Weetman
- 1] Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK [2]
| | - John Essandoh
- 1] Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK [2] Cape Coast Department of Entomology and Wildlife, School of Biological Science, University of Cape Coast, Cape Coast, Ghana
| | - Alexander E Yawson
- 1] Cape Coast Department of Entomology and Wildlife, School of Biological Science, University of Cape Coast, Cape Coast, Ghana [2] Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, PO Box LG 80, Legon, Accra, Ghana
| | - Gareth Maslen
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1RQ, UK
| | - Magnus Manske
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1RQ, UK
| | - Stuart G Field
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
| | | | - Tiago Antão
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Bronwyn MacInnis
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1RQ, UK
| | - Dominic Kwiatkowski
- 1] Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1RQ, UK [2] Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Martin J Donnelly
- 1] Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK [2] Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1RQ, UK
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Cruickshank TE, Hahn MW. Reanalysis suggests that genomic islands of speciation are due to reduced diversity, not reduced gene flow. Mol Ecol 2014; 23:3133-57. [DOI: 10.1111/mec.12796] [Citation(s) in RCA: 764] [Impact Index Per Article: 76.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 12/18/2022]
Affiliation(s)
| | - Matthew W. Hahn
- Department of Biology; Indiana University; Bloomington IN 47405 USA
- School of Informatics and Computing; Indiana University; Bloomington IN 47405 USA
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Arnal A, Kengne P, Brengues C, Dabire KR, Diabate A, Bassene H, Simard F. Genetic polymorphism at an odorant receptor gene (Or39) among mosquitoes of the Anopheles gambiae complex in Senegal (West Africa). BMC Res Notes 2014; 7:321. [PMID: 24886539 PMCID: PMC4048261 DOI: 10.1186/1756-0500-7-321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/21/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Olfaction plays a significant role in insect behavior during critical steps of their life-cycle, such as host-seeking during foraging or the search for a mate. Here, we explored genetic polymorphism within and divergence between sibling species of the African malaria mosquito, Anopheles gambiae sensu lato in the gene sequence and encoded peptides of an odorant receptor, Or39. This study included sympatric specimens of An. gambiae sensu stricto, An. coluzzii and An. arabiensis sampled together in the village of Dielmo, Senegal. RESULTS A 1,601 bp genomic sequence composed of 6 exons and 5 introns was obtained for Or39 from 6-8 mosquitoes in each of the 3 species. DNA sequence analysis revealed a high level of molecular polymorphism (π = 0.0154; Haplotype diversity = 0.867) and high overall genetic differentiation between taxa (Fst > 0.92, P < 0.01). In total, 50 parsimony informative sites were recorded. Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein. Each of the 6 different identified peptides was species-specific and none was shared across species. Most aminoacid changes were located on the intracellular domains of the protein. However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain. CONCLUSIONS Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.
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Affiliation(s)
- Audrey Arnal
- Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France
| | - Pierre Kengne
- Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Cecile Brengues
- Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France
| | - Kounbobr Roch Dabire
- Institut de Recherche en Sciences de la Santé (IRSS), P.O. Box 545, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé (IRSS), P.O. Box 545, Bobo-Dioulasso, Burkina Faso
| | - Hubert Bassene
- UMR 198 URMITE, Campus International IRD/UCAD de Hann, Dakar, Senegal
| | - Frederic Simard
- Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France
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Turner TL. Fine-mapping natural alleles: quantitative complementation to the rescue. Mol Ecol 2014; 23:2377-82. [PMID: 24628660 DOI: 10.1111/mec.12719] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/06/2014] [Accepted: 03/08/2014] [Indexed: 12/15/2022]
Abstract
Mapping the genes responsible for natural variation and divergence is a challenging task. Many studies have mapped genes to genomic regions or generated lists of candidates, but few studies have implicated specific genes with a high standard of evidence. I propose that combining recent advances in genomic engineering with a modified version of the quantitative complementation test will help turn candidate genes into causal genes. By creating loss-of-function mutations in natural strains, and using these mutations to quantitatively fail-to-complement natural alleles, fine mapping should be greatly facilitated. As an example, I propose that the CRISPR/Cas9 system could be combined with the FLP/FRT system to fine-map genes in the numerous systems where inversions have frustrated these efforts.
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Affiliation(s)
- Thomas L Turner
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Noble Hall, Room 2128, Santa Barbara, CA, 93106-9620, USA
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Assogba BS, Djogbénou L, Saizonou J, Diabaté A, Dabiré RK, Moiroux N, Gilles JR, Makoutodé M, Baldet T. Characterization of swarming and mating behaviour between Anopheles coluzzii and Anopheles melas in a sympatry area of Benin. Acta Trop 2014; 132 Suppl:S53-63. [PMID: 24113221 DOI: 10.1016/j.actatropica.2013.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/04/2013] [Accepted: 09/07/2013] [Indexed: 11/27/2022]
Abstract
The swarm structure of two sibling species, Anopheles gambiae coluzzii and Anopheles melas, was characterize to explore the ecological and environmental parameters associated with the formation of swarms and their spatial distribution. Swarms and breeding sites were searched and sampled between January and December 2010, and larval and adult samples were identified by PCR. During the dry season, 456 swarms of An. gambiae s.l. were sampled from 38 swarm sites yielding a total of 23,274 males and 76 females. Of these 38 swarming sites, 18 were composed exclusively of An. gambiae coluzzii and 20 exclusively of An. melas, presenting clear evidence of reproductive swarm segregation. The species makeup of couples sampled from swarms also demonstrated assortative mating. The swarm site localization was close to human dwellings in the case of the An. gambiae coluzzii and on salt production sites for An. melas. At the peak of the rainy season, swarms of An. melas were absent. These findings offer evidence that the ecological speciation of these two sibling species of mosquitoes is associated with spatial swarm segregation and assortative mating, providing strong support for the hypothesis that mate recognition is currently maintaining adaptive differentiation and promoting ecological speciation. Further studies on the swarming and mating systems of An. gambiae, with the prospect of producing a predictive model of swarm distribution, are needed to inform any future efforts to implement strategies based on the use of GMM or SIT.
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