1
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Wilhoit KT, Alexander EP, Blackmon H. Worse than nothing at all: the inequality of fusions joining autosomes to the PAR and non-PAR portions of sex chromosomes. PeerJ 2024; 12:e17740. [PMID: 39071118 PMCID: PMC11276758 DOI: 10.7717/peerj.17740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 06/24/2024] [Indexed: 07/30/2024] Open
Abstract
Chromosomal fusions play an integral role in genome remodeling and karyotype evolution. Fusions that join a sex chromosome to an autosome are particularly abundant across the tree of life. However, previous models on the establishment of such fusions have not accounted for the physical structure of the chromosomes. We predict a fusion joining an autosome to the pseudoautosomal region (PAR) of a sex chromosome will not remain stable, and the fusion will switch from the X to the Y chromosome each generation due to recombination. We have produced a forward-time population genetic simulation to explore the outcomes of fusions to both the PAR and non-PAR of sex chromosomes. The model can simulate the fusion of an autosome containing a sexually antagonistic locus to either the PAR or non-PAR end of a sex chromosome. Our model is diploid, two-locus, and biallelic. Our results show a clear pattern where fusions to the non-PAR are favored in the presence of sexual antagonism, whereas fusions to the PAR are disfavored in the presence of sexual antagonism.
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Affiliation(s)
- Kayla T. Wilhoit
- Biomedical Sciences Program, Texas A&M University, College Station, TX, United States of America
- Department of Biology, Texas A&M University, College Station, TX, United States of America
- University Program in Genetics and Genomics, Duke University, Durham, NC, United States of America
| | - Emmarie P. Alexander
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States of America
- Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, United States of America
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX, United States of America
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States of America
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2
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Xu L, Ren Y, Wu J, Cui T, Dong R, Huang C, Feng Z, Zhang T, Yang P, Yuan J, Xu X, Liu J, Wang J, Chen W, Mi D, Irwin DM, Yan Y, Xu L, Yu X, Li G. Evolution and expression patterns of the neo-sex chromosomes of the crested ibis. Nat Commun 2024; 15:1670. [PMID: 38395916 PMCID: PMC10891136 DOI: 10.1038/s41467-024-46052-x] [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: 06/21/2023] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Bird sex chromosomes play a unique role in sex-determination, and affect the sexual morphology and behavior of bird species. Core waterbirds, a major clade of birds, share the common characteristics of being sexually monomorphic and having lower levels of inter-sexual conflict, yet their sex chromosome evolution remains poorly understood. Here, by we analyse of a chromosome-level assembly of a female crested ibis (Nipponia nippon), a typical core waterbird. We identify neo-sex chromosomes resulting from fusion of microchromosomes with ancient sex chromosomes. These fusion events likely occurred following the divergence of Threskiornithidae and Ardeidae. The neo-W chromosome of the crested ibis exhibits the characteristics of slow degradation, which is reflected in its retention of abundant gametologous genes. Neo-W chromosome genes display an apparent ovary-biased gene expression, which is largely driven by genes that are retained on the crested ibis W chromosome but lost in other bird species. These results provide new insights into the evolutionary history and expression patterns for the sex chromosomes of bird species.
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Affiliation(s)
- Lulu Xu
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yandong Ren
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Jiahong Wu
- MOE Key Laboratory of Freshwater Fish Reproduction and Development, School of Life Sciences, Southwest University, Chongqing, China
| | - Tingting Cui
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Rong Dong
- Research Center for Qinling Giant Panda, Shaanxi Academy of Forestry, Xi'an, China
| | - Chen Huang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Zhe Feng
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Tianmin Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Peng Yang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Jiaqing Yuan
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Xiao Xu
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Jiao Liu
- MOE Key Laboratory of Freshwater Fish Reproduction and Development, School of Life Sciences, Southwest University, Chongqing, China
| | - Jinhong Wang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Wu Chen
- Guangzhou Wildlife Research Center, Guangzhou Zoo, Guangzhou, China
| | - Da Mi
- Xi'an Haorui Genomics Technology Co., LTD, Xi'an, China
| | - David M Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Yaping Yan
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Luohao Xu
- MOE Key Laboratory of Freshwater Fish Reproduction and Development, School of Life Sciences, Southwest University, Chongqing, China.
| | - Xiaoping Yu
- College of Life Sciences, Shaanxi Normal University, Xi'an, China.
| | - Gang Li
- College of Life Sciences, Shaanxi Normal University, Xi'an, China.
- Guangzhou Wildlife Research Center, Guangzhou Zoo, Guangzhou, China.
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3
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Bascón-Cardozo K, Bours A, Manthey G, Durieux G, Dutheil JY, Pruisscher P, Odenthal-Hesse L, Liedvogel M. Fine-Scale Map Reveals Highly Variable Recombination Rates Associated with Genomic Features in the Eurasian Blackcap. Genome Biol Evol 2024; 16:evad233. [PMID: 38198800 PMCID: PMC10781513 DOI: 10.1093/gbe/evad233] [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] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
Recombination is responsible for breaking up haplotypes, influencing genetic variability, and the efficacy of selection. Bird genomes lack the protein PR domain-containing protein 9, a key determinant of recombination dynamics in most metazoans. Historical recombination maps in birds show an apparent stasis in positioning recombination events. This highly conserved recombination pattern over long timescales may constrain the evolution of recombination in birds. At the same time, extensive variation in recombination rate is observed across the genome and between different species of birds. Here, we characterize the fine-scale historical recombination map of an iconic migratory songbird, the Eurasian blackcap (Sylvia atricapilla), using a linkage disequilibrium-based approach that accounts for population demography. Our results reveal variable recombination rates among and within chromosomes, which associate positively with nucleotide diversity and GC content and negatively with chromosome size. Recombination rates increased significantly at regulatory regions but not necessarily at gene bodies. CpG islands are associated strongly with recombination rates, though their specific position and local DNA methylation patterns likely influence this relationship. The association with retrotransposons varied according to specific family and location. Our results also provide evidence of heterogeneous intrachromosomal conservation of recombination maps between the blackcap and its closest sister taxon, the garden warbler. These findings highlight the considerable variability of recombination rates at different scales and the role of specific genomic features in shaping this variation. This study opens the possibility of further investigating the impact of recombination on specific population-genomic features.
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Affiliation(s)
- Karen Bascón-Cardozo
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Andrea Bours
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Georg Manthey
- Institute of Avian Research “Vogelwarte Helgoland”, Wilhelmshaven 26386, Germany
| | - Gillian Durieux
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Julien Y Dutheil
- Department for Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Peter Pruisscher
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
- Department of Zoology, Stockholm University, Stockholm SE-106 91, Sweden
| | - Linda Odenthal-Hesse
- Department Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Miriam Liedvogel
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
- Institute of Avian Research “Vogelwarte Helgoland”, Wilhelmshaven 26386, Germany
- Department of Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, Oldenburg 26129, Germany
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4
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Charlesworth D, Qiu S, Bergero R, Gardner J, Keegan K, Yong L, Hastings A, Konczal M. Has recombination changed during the recent evolution of the guppy Y chromosome? Genetics 2024; 226:iyad198. [PMID: 37956094 DOI: 10.1093/genetics/iyad198] [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: 09/27/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Genome sequencing and genetic mapping of molecular markers have demonstrated nearly complete Y-linkage across much of the guppy (Poecilia reticulata) XY chromosome pair. Predominant Y-linkage of factors controlling visible male-specific coloration traits also suggested that these polymorphisms are sexually antagonistic (SA). However, occasional exchanges with the X are detected, and recombination patterns also appear to differ between natural guppy populations, suggesting ongoing evolution of recombination suppression under selection created by partially sex-linked SA polymorphisms. We used molecular markers to directly estimate genetic maps in sires from 4 guppy populations. The maps are very similar, suggesting that their crossover patterns have not recently changed. Our maps are consistent with population genomic results showing that variants within the terminal 5 Mb of the 26.5 Mb sex chromosome, chromosome 12, are most clearly associated with the maleness factor, albeit incompletely. We also confirmed occasional crossovers proximal to the male-determining region, defining a second, rarely recombining, pseudo-autosomal region, PAR2. This fish species may therefore have no completely male-specific region (MSY) more extensive than the male-determining factor. The positions of the few crossover events suggest a location for the male-determining factor within a physically small repetitive region. A sex-reversed XX male had few crossovers in PAR2, suggesting that this region's low crossover rate depends on the phenotypic, not the genetic, sex. Thus, rare individuals whose phenotypic and genetic sexes differ, and/or occasional PAR2 crossovers in males can explain the failure to detect fully Y-linked variants.
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Affiliation(s)
- Deborah Charlesworth
- School of Biological Sciences, Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3LF, UK
| | - Suo Qiu
- School of Biological Sciences, Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3LF, UK
| | - Roberta Bergero
- Scottish Rural Agricultural College, Peter Wilson Building, King's Buildings, W Mains Rd, Edinburgh EH9 3JG, UK
| | - Jim Gardner
- School of Biological Sciences, Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3LF, UK
| | - Karen Keegan
- School of Biological Sciences, Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3LF, UK
| | - Lengxob Yong
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK
- South Carolina Department of Natural Resources, Marine Resources Research Institute, P.O. Box 12559 Charleston, SC 29422-2559, USA
| | - Abigail Hastings
- School of Biological Sciences, Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3LF, UK
| | - Mateusz Konczal
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, 60-614 Poznań, Poland
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5
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Yamaguchi K, Uno Y, Kadota M, Nishimura O, Nozu R, Murakumo K, Matsumoto R, Sato K, Kuraku S. Elasmobranch genome sequencing reveals evolutionary trends of vertebrate karyotype organization. Genome Res 2023; 33:1527-1540. [PMID: 37591668 PMCID: PMC10620051 DOI: 10.1101/gr.276840.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 07/31/2023] [Indexed: 08/19/2023]
Abstract
Genomic studies of vertebrate chromosome evolution have long been hindered by the scarcity of chromosome-scale DNA sequences of some key taxa. One of those limiting taxa has been the elasmobranchs (sharks and rays), which harbor species often with numerous chromosomes and enlarged genomes. Here, we report the chromosome-scale genome assembly for the zebra shark Stegostoma tigrinum, an endangered species that has a relatively small genome among sharks (3.71 Gb), as well as for the whale shark Rhincodon typus Our analysis using a male-female comparison identified an X Chromosome, the first genomically characterized shark sex chromosome. The X Chromosome harbors the Hox C cluster whose intact linkage has not been shown for an elasmobranch fish. The sequenced shark genomes show a gradualism of chromosome length with remarkable length-dependent characteristics-shorter chromosomes tend to have higher GC content, gene density, synonymous substitution rate, and simple tandem repeat content as well as smaller gene length and lower interspersed repeat content. We challenge the traditional binary classification of karyotypes as with and without so-called microchromosomes. Even without microchromosomes, the length-dependent characteristics persist widely in nonmammalian vertebrates. Our investigation of elasmobranch karyotypes underpins their unique characteristics and provides clues for understanding how vertebrate karyotypes accommodate intragenomic heterogeneity to realize a complex readout. It also paves the way to dissecting more genomes with variable sizes to be sequenced at high quality.
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Affiliation(s)
- Kazuaki Yamaguchi
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), 650-0047, Kobe, Japan
| | - Yoshinobu Uno
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), 650-0047, Kobe, Japan
| | - Mitsutaka Kadota
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), 650-0047, Kobe, Japan
| | - Osamu Nishimura
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), 650-0047, Kobe, Japan
| | - Ryo Nozu
- Okinawa Churashima Research Center, Okinawa Churashima Foundation, 905-0206, Okinawa, Japan
| | | | | | - Keiichi Sato
- Okinawa Churashima Research Center, Okinawa Churashima Foundation, 905-0206, Okinawa, Japan
- Okinawa Churaumi Aquarium, 905-0206, Okinawa, Japan
| | - Shigehiro Kuraku
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), 650-0047, Kobe, Japan;
- Molecular Life History Laboratory, Department of Genomics and Evolutionary Biology, National Institute of Genetics, 411-8540, Mishima, Japan
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), 411-8540, Mishima, Japan
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6
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Catalán A, Merondun J, Knief U, Wolf JBW. Chromatin accessibility, not 5mC methylation covaries with partial dosage compensation in crows. PLoS Genet 2023; 19:e1010901. [PMID: 37747941 PMCID: PMC10575545 DOI: 10.1371/journal.pgen.1010901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/13/2023] [Accepted: 08/07/2023] [Indexed: 09/27/2023] Open
Abstract
The evolution of genetic sex determination is often accompanied by degradation of the sex-limited chromosome. Male heterogametic systems have evolved convergent, epigenetic mechanisms restoring the resulting imbalance in gene dosage between diploid autosomes (AA) and the hemizygous sex chromosome (X). Female heterogametic systems (AAf Zf, AAm ZZm) tend to only show partial dosage compensation (0.5 < Zf:AAf < 1) and dosage balance (0.5
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Affiliation(s)
- Ana Catalán
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Justin Merondun
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Ulrich Knief
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
- Evolutionary Biology & Ecology,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Jochen B. W. Wolf
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
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7
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Yazdi HP, Olito C, Kawakami T, Unneberg P, Schou MF, Cloete SWP, Hansson B, Cornwallis CK. The evolutionary maintenance of ancient recombining sex chromosomes in the ostrich. PLoS Genet 2023; 19:e1010801. [PMID: 37390104 DOI: 10.1371/journal.pgen.1010801] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/28/2023] [Indexed: 07/02/2023] Open
Abstract
Sex chromosomes have evolved repeatedly across the tree of life and often exhibit extreme size dimorphism due to genetic degeneration of the sex-limited chromosome (e.g. the W chromosome of some birds and Y chromosome of mammals). However, in some lineages, ancient sex-limited chromosomes have escaped degeneration. Here, we study the evolutionary maintenance of sex chromosomes in the ostrich (Struthio camelus), where the W remains 65% the size of the Z chromosome, despite being more than 100 million years old. Using genome-wide resequencing data, we show that the population scaled recombination rate of the pseudoautosomal region (PAR) is higher than similar sized autosomes and is correlated with pedigree-based recombination rate in the heterogametic females, but not homogametic males. Genetic variation within the sex-linked region (SLR) (π = 0.001) was significantly lower than in the PAR, consistent with recombination cessation. Conversely, genetic variation across the PAR (π = 0.0016) was similar to that of autosomes and dependent on local recombination rates, GC content and to a lesser extent, gene density. In particular, the region close to the SLR was as genetically diverse as autosomes, likely due to high recombination rates around the PAR boundary restricting genetic linkage with the SLR to only ~50Kb. The potential for alleles with antagonistic fitness effects in males and females to drive chromosome degeneration is therefore limited. While some regions of the PAR had divergent male-female allele frequencies, suggestive of sexually antagonistic alleles, coalescent simulations showed this was broadly consistent with neutral genetic processes. Our results indicate that the degeneration of the large and ancient sex chromosomes of the ostrich may have been slowed by high recombination in the female PAR, reducing the scope for the accumulation of sexually antagonistic variation to generate selection for recombination cessation.
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Affiliation(s)
| | - Colin Olito
- Department of Biology, Lund University, Lund, Sweden
| | - Takeshi Kawakami
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Embark Veterinary, Inc., Boston, Massachusetts, United States of America
| | - Per Unneberg
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Mads F Schou
- Department of Biology, Lund University, Lund, Sweden
| | - Schalk W P Cloete
- Directorate Animal Sciences, Western Cape Department of Agriculture, Elsenburg, South Africa
- Department of Animal Sciences, Stellenbosch University, Matieland, South Africa
| | - Bengt Hansson
- Department of Biology, Lund University, Lund, Sweden
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8
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Burley JT, Orzechowski SCM, Sin SYW, Edwards SV. Whole-genome phylogeography of the blue-faced honeyeater (Entomyzon cyanotis) and discovery and characterization of a neo-Z chromosome. Mol Ecol 2023; 32:1248-1270. [PMID: 35797346 DOI: 10.1111/mec.16604] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 06/22/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022]
Abstract
Whole-genome surveys of genetic diversity and geographic variation often yield unexpected discoveries of novel structural variation, which long-read DNA sequencing can help clarify. Here, we report on whole-genome phylogeography of a bird exhibiting classic vicariant geographies across Australia and New Guinea, the blue-faced honeyeater (Entomyzon cyanotis), and the discovery and characterization of a novel neo-Z chromosome by long-read sequencing. Using short-read genome-wide SNPs, we inferred population divergence events within E. cyanotis across the Carpentarian and other biogeographic barriers during the Pleistocene (~0.3-1.7 Ma). Evidence for introgression between nonsister populations supports a hypothesis of reticulate evolution around a triad of dynamic barriers around Pleistocene Lake Carpentaria between Australia and New Guinea. During this phylogeographic survey, we discovered a large (134 Mbp) neo-Z chromosome and we explored its diversity, divergence and introgression landscape. We show that, as in some sylvioid passerine birds, a fusion occurred between chromosome 5 and the Z chromosome to form a neo-Z chromosome; and in E. cyanotis, the ancestral pseudoautosomal region (PAR) appears nonrecombinant between Z and W, along with most of the fused chromosome 5. The added recombination-suppressed portion of the neo-Z (~37.2 Mbp) displays reduced diversity and faster population genetic differentiation compared with the ancestral-Z. Yet, the new PAR (~17.4 Mbp) shows elevated diversity and reduced differentiation compared to autosomes, potentially resulting from introgression. In our case, long-read sequencing helped clarify the genomic landscape of population divergence on autosomes and sex chromosomes in a species where prior knowledge of genome structure was still incomplete.
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Affiliation(s)
- John T Burley
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA.,Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden.,Department of Ecology Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA.,Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | | | - Simon Yung Wa Sin
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA.,School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Scott V Edwards
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
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9
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Lipkin E, Smith J, Soller M, Burt DW, Fulton JE. Sex Differences in Response to Marek's Disease: Mapping Quantitative Trait Loci Regions (QTLRs) to the Z Chromosome. Genes (Basel) 2022; 14:genes14010020. [PMID: 36672761 PMCID: PMC9859034 DOI: 10.3390/genes14010020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Marek's Disease (MD) has a significant impact on both the global poultry economy and animal welfare. The disease pathology can include neurological damage and tumour formation. Sexual dimorphism in immunity and known higher susceptibility of females to MD makes the chicken Z chromosome (GGZ) a particularly attractive target to study the chicken MD response. Previously, we used a Hy-Line F6 population from a full-sib advanced intercross line to map MD QTL regions (QTLRs) on all chicken autosomes. Here, we mapped MD QTLRs on GGZ in the previously utilized F6 population with individual genotypes and phenotypes, and in eight elite commercial egg production lines with daughter-tested sires and selective DNA pooling (SDP). Four MD QTLRs were found from each analysis. Some of these QTLRs overlap regions from previous reports. All QTLRs were tested by individuals from the same eight lines used in the SDP and genotyped with markers located within and around the QTLRs. All QTLRs were confirmed. The results exemplify the complexity of MD resistance in chickens and the complex distribution of p-values and Linkage Disequilibrium (LD) pattern and their effect on localization of the causative elements. Considering the fragments and interdigitated LD blocks while using LD to aid localization of causative elements, one must look beyond the non-significant markers, for possible distant markers and blocks in high LD with the significant block. The QTLRs found here may explain at least part of the gender differences in MD tolerance, and provide targets for mitigating the effects of MD.
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Affiliation(s)
- Ehud Lipkin
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
- Correspondence: (E.L.); (J.S.)
| | - Jacqueline Smith
- The Roslin Institute and Royal (Dick) School of Veterinary Studies R(D)SVS, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
- Correspondence: (E.L.); (J.S.)
| | - Morris Soller
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - David W. Burt
- The Roslin Institute and Royal (Dick) School of Veterinary Studies R(D)SVS, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| | - Janet E. Fulton
- Hy-Line International, P.O. Box 310, 2583 240th St., Dallas Center, IA 50063, USA
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10
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de Manuel M, Wu FL, Przeworski M. A paternal bias in germline mutation is widespread in amniotes and can arise independently of cell division numbers. eLife 2022; 11:e80008. [PMID: 35916372 PMCID: PMC9439683 DOI: 10.7554/elife.80008] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
In humans and other mammals, germline mutations are more likely to arise in fathers than in mothers. Although this sex bias has long been attributed to DNA replication errors in spermatogenesis, recent evidence from humans points to the importance of mutagenic processes that do not depend on cell division, calling into question our understanding of this basic phenomenon. Here, we infer the ratio of paternal-to-maternal mutations, α, in 42 species of amniotes, from putatively neutral substitution rates of sex chromosomes and autosomes. Despite marked differences in gametogenesis, physiologies and environments across species, fathers consistently contribute more mutations than mothers in all the species examined, including mammals, birds, and reptiles. In mammals, α is as high as 4 and correlates with generation times; in birds and snakes, α appears more stable around 2. These observations are consistent with a simple model, in which mutations accrue at equal rates in both sexes during early development and at a higher rate in the male germline after sexual differentiation, with a conserved paternal-to-maternal ratio across species. Thus, α may reflect the relative contributions of two or more developmental phases to total germline mutations, and is expected to depend on generation time even if mutations do not track cell divisions.
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Affiliation(s)
- Marc de Manuel
- Department of Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Felix L Wu
- Department of Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Molly Przeworski
- Department of Systems Biology, Columbia UniversityNew YorkUnited States
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11
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Ponnikas S, Sigeman H, Lundberg M, Hansson B. Extreme variation in recombination rate and genetic diversity along the Sylvioidea neo-sex chromosome. Mol Ecol 2022; 31:3566-3583. [PMID: 35578784 PMCID: PMC9327509 DOI: 10.1111/mec.16532] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/13/2022] [Accepted: 05/04/2022] [Indexed: 12/03/2022]
Abstract
Recombination strongly impacts sequence evolution by affecting the extent of linkage and the efficiency of selection. Here, we study recombination over the Z chromosome in great reed warblers (Acrocephalus arundinaceus) using pedigree-based linkage mapping. This species has extended Z and W chromosomes ("neo-sex chromosomes") formed by a fusion between a part of chromosome 4A and the ancestral sex chromosomes, which provides a unique opportunity to assess recombination and sequence evolution in sex-linked regions of different ages. We assembled an 87.54 Mbp and 90.19 cM large Z with a small pseudoautosomal region (0.89 Mbp) at one end and the fused Chr4A-part at the other end of the chromosome. A prominent feature in our data was an extreme variation in male recombination rate along Z with high values at both chromosome ends, but an apparent lack of recombination over a substantial central section, covering 78% of the chromosome. The nonrecombining region showed a drastic loss of genetic diversity and accumulation of repeats compared to the recombining parts. Thus, our data emphasize a key role of recombination in affecting local levels of polymorphism. Nonetheless, the evolutionary rate of genes (dN/dS) did not differ between high and low recombining regions, suggesting that the efficiency of selection on protein-coding sequences can be maintained also at very low levels of recombination. Finally, the Chr4A-derived part showed a similar recombination rate as the part of the ancestral Z that did recombine, but its sequence characteristics reflected both its previous autosomal, and current Z-linked, recombination patterns.
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Affiliation(s)
- Suvi Ponnikas
- Department of BiologyLund UniversityLundSweden
- Ecology and Genetics Research UnitUniversity of OuluOuluFinland
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12
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Spottiswoode CN, Tong W, Jamie GA, Stryjewski KF, DaCosta JM, Kuras ER, Green A, Hamama S, Taylor IG, Moya C, Sorenson MD. Genetic architecture facilitates then constrains adaptation in a host-parasite coevolutionary arms race. Proc Natl Acad Sci U S A 2022; 119:e2121752119. [PMID: 35412865 PMCID: PMC9170059 DOI: 10.1073/pnas.2121752119] [Citation(s) in RCA: 6] [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: 11/30/2021] [Accepted: 02/11/2022] [Indexed: 12/15/2022] Open
Abstract
In coevolutionary arms races, interacting species impose selection on each other, generating reciprocal adaptations and counter adaptations. This process is typically enhanced by genetic recombination and heterozygosity, but these sources of evolutionary novelty may be secondarily lost when uniparental inheritance evolves to ensure the integrity of sex-linked adaptations. We demonstrate that host-specific egg mimicry in the African cuckoo finch Anomalospiza imberbis is maternally inherited, confirming the validity of an almost century-old hypothesis. We further show that maternal inheritance not only underpins the mimicry of different host species but also additional mimetic diversification that approximates the range of polymorphic egg “signatures” that have evolved within host species as an escalated defense against parasitism. Thus, maternal inheritance has enabled the evolution and maintenance of nested levels of mimetic specialization in a single parasitic species. However, maternal inheritance and the lack of sexual recombination likely disadvantage cuckoo finches by stifling further adaptation in the ongoing arms races with their individual hosts, which we show have retained biparental inheritance of egg phenotypes. The inability to generate novel genetic combinations likely prevents cuckoo finches from mimicking certain host phenotypes that are currently favored by selection (e.g., the olive-green colored eggs laid by some tawny-flanked prinia, Prinia subflava, females). This illustrates an important cost of coding coevolved adaptations on the nonrecombining sex chromosome, which may impede further coevolutionary change by effectively reversing the advantages of sexual reproduction in antagonistic coevolution proposed by the Red Queen hypothesis.
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Affiliation(s)
- Claire N. Spottiswoode
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
- FitzPatrick Institute of African Ornithology, Department of Science and Technology–National Research Foundation Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | - Wenfei Tong
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - Gabriel A. Jamie
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
- FitzPatrick Institute of African Ornithology, Department of Science and Technology–National Research Foundation Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | | | - Jeffrey M. DaCosta
- Department of Biology, Boston University, Boston, MA 02215
- Biology Department, Boston College, Chestnut Hill, MA 02467
| | - Evan R. Kuras
- Department of Biology, Boston University, Boston, MA 02215
| | - Ailsa Green
- Chenga Farm, Choma, Southern Province, Zambia
| | - Silky Hamama
- Musumanene Farm, Choma, Southern Province, Zambia
| | | | - Collins Moya
- Musumanene Farm, Choma, Southern Province, Zambia
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13
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Peona V, Blom MPK, Xu L, Burri R, Sullivan S, Bunikis I, Liachko I, Haryoko T, Jønsson KA, Zhou Q, Irestedt M, Suh A. Identifying the causes and consequences of assembly gaps using a multiplatform genome assembly of a bird-of-paradise. Mol Ecol Resour 2021; 21:263-286. [PMID: 32937018 PMCID: PMC7757076 DOI: 10.1111/1755-0998.13252] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 01/09/2023]
Abstract
Genome assemblies are currently being produced at an impressive rate by consortia and individual laboratories. The low costs and increasing efficiency of sequencing technologies now enable assembling genomes at unprecedented quality and contiguity. However, the difficulty in assembling repeat-rich and GC-rich regions (genomic "dark matter") limits insights into the evolution of genome structure and regulatory networks. Here, we compare the efficiency of currently available sequencing technologies (short/linked/long reads and proximity ligation maps) and combinations thereof in assembling genomic dark matter. By adopting different de novo assembly strategies, we compare individual draft assemblies to a curated multiplatform reference assembly and identify the genomic features that cause gaps within each assembly. We show that a multiplatform assembly implementing long-read, linked-read and proximity sequencing technologies performs best at recovering transposable elements, multicopy MHC genes, GC-rich microchromosomes and the repeat-rich W chromosome. Telomere-to-telomere assemblies are not a reality yet for most organisms, but by leveraging technology choice it is now possible to minimize genome assembly gaps for downstream analysis. We provide a roadmap to tailor sequencing projects for optimized completeness of both the coding and noncoding parts of nonmodel genomes.
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Affiliation(s)
- Valentina Peona
- Department of Ecology and Genetics—Evolutionary BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- Department of Organismal Biology—Systematic BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
| | - Mozes P. K. Blom
- Department of Bioinformatics and GeneticsSwedish Museum of Natural HistoryStockholmSweden
- Museum für NaturkundeLeibniz Institut für Evolutions‐ und BiodiversitätsforschungBerlinGermany
| | - Luohao Xu
- Department of Neurosciences and Developmental BiologyUniversity of ViennaViennaAustria
| | - Reto Burri
- Department of Population EcologyInstitute of Ecology and EvolutionFriedrich‐Schiller‐University JenaJenaGermany
| | | | - Ignas Bunikis
- Department of Immunology, Genetics and PathologyScience for Life LaboratoryUppsala Genome CenterUppsala UniversityUppsalaSweden
| | | | - Tri Haryoko
- Research Centre for BiologyMuseum Zoologicum BogorienseIndonesian Institute of Sciences (LIPI)CibinongIndonesia
| | - Knud A. Jønsson
- Natural History Museum of DenmarkUniversity of CopenhagenCopenhagenDenmark
| | - Qi Zhou
- Department of Neurosciences and Developmental BiologyUniversity of ViennaViennaAustria
- MOE Laboratory of Biosystems Homeostasis & ProtectionLife Sciences InstituteZhejiang UniversityHangzhouChina
- Center for Reproductive MedicineThe 2nd Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Martin Irestedt
- Department of Bioinformatics and GeneticsSwedish Museum of Natural HistoryStockholmSweden
| | - Alexander Suh
- Department of Ecology and Genetics—Evolutionary BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- Department of Organismal Biology—Systematic BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- School of Biological Sciences—Organisms and the EnvironmentUniversity of East AngliaNorwichUK
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14
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Yazdi HP, Silva WTAF, Suh A. Why Do Some Sex Chromosomes Degenerate More Slowly Than Others? The Odd Case of Ratite Sex Chromosomes. Genes (Basel) 2020; 11:E1153. [PMID: 33007827 PMCID: PMC7601716 DOI: 10.3390/genes11101153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 01/10/2023] Open
Abstract
The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes in ratites is not clear. Degeneration of the W chromosome might have halted or slowed down due to a multitude of reasons ranging from selective processes, such as a less pronounced effect of sexually antagonistic selection, to neutral processes, such as a slower rate of molecular evolution in ratites. The production of genome assemblies and gene expression data for species of Palaeognathae has made it possible, during recent years, to have a closer look at their sex chromosome evolution. Here, we critically evaluate the understanding of the maintenance of recombination in ratites in light of the current data. We conclude by highlighting certain aspects of sex chromosome evolution in ratites that require further research and can potentially increase power for the inference of the unique history of sex chromosome evolution in this lineage of birds.
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Affiliation(s)
| | | | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TU, UK;
- Department of Organismal Biology—Systematic Biology, Uppsala University, SE-752 36 Uppsala, Sweden
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15
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Xu L, Wa Sin SY, Grayson P, Edwards SV, Sackton TB. Evolutionary Dynamics of Sex Chromosomes of Paleognathous Birds. Genome Biol Evol 2020; 11:2376-2390. [PMID: 31329234 PMCID: PMC6735826 DOI: 10.1093/gbe/evz154] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2019] [Indexed: 12/20/2022] Open
Abstract
Standard models of sex chromosome evolution propose that recombination suppression leads to the degeneration of the heterogametic chromosome, as is seen for the Y chromosome in mammals and the W chromosome in most birds. Unlike other birds, paleognaths (ratites and tinamous) possess large nondegenerate regions on their sex chromosomes (PARs or pseudoautosomal regions). It remains unclear why these large PARs are retained over >100 Myr, and how this retention impacts the evolution of sex chromosomes within this system. To address this puzzle, we analyzed Z chromosome evolution and gene expression across 12 paleognaths, several of whose genomes have recently been sequenced. We confirm at the genomic level that most paleognaths retain large PARs. As in other birds, we find that all paleognaths have incomplete dosage compensation on the regions of the Z chromosome homologous to degenerated portions of the W (differentiated regions), but we find no evidence for enrichments of male-biased genes in PARs. We find limited evidence for increased evolutionary rates (faster-Z) either across the chromosome or in differentiated regions for most paleognaths with large PARs, but do recover signals of faster-Z evolution in tinamou species with mostly degenerated W chromosomes, similar to the pattern seen in neognaths. Unexpectedly, in some species, PAR-linked genes evolve faster on average than genes on autosomes, suggested by diverse genomic features to be due to reduced efficacy of selection in paleognath PARs. Our analysis shows that paleognath Z chromosomes are atypical at the genomic level, but the evolutionary forces maintaining largely homomorphic sex chromosomes in these species remain elusive.
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Affiliation(s)
- Luohao Xu
- Department of Molecular Evolution and Development, University of Vienna, Austria
| | - Simon Yung Wa Sin
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Phil Grayson
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
| | - Timothy B Sackton
- Informatics Group, Division of Science, Harvard University
- Corresponding author: E-mail:
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16
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Sigeman H, Ponnikas S, Chauhan P, Dierickx E, Brooke MDL, Hansson B. Repeated sex chromosome evolution in vertebrates supported by expanded avian sex chromosomes. Proc Biol Sci 2019; 286:20192051. [PMID: 31771477 PMCID: PMC6939255 DOI: 10.1098/rspb.2019.2051] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/01/2019] [Indexed: 12/28/2022] Open
Abstract
Sex chromosomes have evolved from the same autosomes multiple times across vertebrates, suggesting that selection for recombination suppression has acted repeatedly and independently on certain genetic backgrounds. Here, we perform comparative genomics of a bird clade (larks and their sister lineage; Alaudidae and Panuridae) where multiple autosome-sex chromosome fusions appear to have formed expanded sex chromosomes. We detected the largest known avian sex chromosome (195.3 Mbp) and show that it originates from fusions between parts of four avian chromosomes: Z, 3, 4A and 5. Within these four chromosomes, we found evidence of five evolutionary strata where recombination had been suppressed at different time points, and show that stratum age explained the divergence rate of Z-W gametologs. Next, we analysed chromosome content and found that chromosome 3 was significantly enriched for genes with predicted sex-related functions. Finally, we demonstrate extensive homology to sex chromosomes in other vertebrate lineages: chromosomes Z, 3, 4A and 5 have independently evolved into sex chromosomes in fish (Z), turtles (Z, 5), lizards (Z, 4A), mammals (Z, 4A) and frogs (Z, 3, 4A, 5). Our results provide insights into and support for repeated evolution of sex chromosomes in vertebrates.
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Affiliation(s)
- Hanna Sigeman
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Suvi Ponnikas
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Pallavi Chauhan
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Elisa Dierickx
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB23EJ, UK
| | - M. de L. Brooke
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB23EJ, UK
| | - Bengt Hansson
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
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17
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Nadachowska-Brzyska K, Burri R, Ellegren H. Footprints of adaptive evolution revealed by whole Z chromosomes haplotypes in flycatchers. Mol Ecol 2019; 28:2290-2304. [PMID: 30653779 PMCID: PMC6852393 DOI: 10.1111/mec.15021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 01/19/2023]
Abstract
Detecting positive selection using genomic data is critical to understanding the role of adaptive evolution. Of particular interest in this context is sex chromosomes since they are thought to play a special role in local adaptation and speciation. We sought to circumvent the challenges associated with statistical phasing when using haplotype-based statistics in sweep scans by benefitting from that whole chromosome haplotypes of the sex chromosomes can be obtained by resequencing of individuals of the hemizygous sex. We analyzed whole Z chromosome haplotypes from 100 females from several populations of four black and white flycatcher species (in birds, females are ZW and males ZZ). Based on integrated haplotype score (iHS) and number of segregating sites by length (nSL) statistics, we found strong and frequent haplotype structure in several regions of the Z chromosome in each species. Most of these sweep signals were population-specific, with essentially no evidence for regions under selection shared among species. Some completed sweeps were revealed by the cross-population extended haplotype homozygosity (XP-EHH) statistic. Importantly, by using statistically phased Z chromosome data from resequencing of males, we failed to recover the signals of selection detected in analyses based on whole chromosome haplotypes from females; instead, what likely represent false signals of selection were frequently seen. This highlights the power issues in statistical phasing and cautions against conclusions from selection scans using such data. The detection of frequent selective sweeps on the avian Z chromosome supports a large role of sex chromosomes in adaptive evolution.
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Affiliation(s)
| | - Reto Burri
- Department of Evolutionary Biology, University of Uppsala, Uppsala, Sweden.,Department of Population Ecology, Friedrich Schiller University Jena, Jena, Germany
| | - Hans Ellegren
- Department of Evolutionary Biology, University of Uppsala, Uppsala, Sweden
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18
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Dynamic evolutionary history and gene content of sex chromosomes across diverse songbirds. Nat Ecol Evol 2019; 3:834-844. [DOI: 10.1038/s41559-019-0850-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/22/2019] [Indexed: 11/09/2022]
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19
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Schield DR, Card DC, Hales NR, Perry BW, Pasquesi GM, Blackmon H, Adams RH, Corbin AB, Smith CF, Ramesh B, Demuth JP, Betrán E, Tollis M, Meik JM, Mackessy SP, Castoe TA. The origins and evolution of chromosomes, dosage compensation, and mechanisms underlying venom regulation in snakes. Genome Res 2019; 29:590-601. [PMID: 30898880 PMCID: PMC6442385 DOI: 10.1101/gr.240952.118] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 02/15/2019] [Indexed: 01/28/2023]
Abstract
Here we use a chromosome-level genome assembly of a prairie rattlesnake (Crotalus viridis), together with Hi-C, RNA-seq, and whole-genome resequencing data, to study key features of genome biology and evolution in reptiles. We identify the rattlesnake Z Chromosome, including the recombining pseudoautosomal region, and find evidence for partial dosage compensation driven by an evolutionary accumulation of a female-biased up-regulation mechanism. Comparative analyses with other amniotes provide new insight into the origins, structure, and function of reptile microchromosomes, which we demonstrate have markedly different structure and function compared to macrochromosomes. Snake microchromosomes are also enriched for venom genes, which we show have evolved through multiple tandem duplication events in multiple gene families. By overlaying chromatin structure information and gene expression data, we find evidence for venom gene-specific chromatin contact domains and identify how chromatin structure guides precise expression of multiple venom gene families. Further, we find evidence for venom gland-specific transcription factor activity and characterize a complement of mechanisms underlying venom production and regulation. Our findings reveal novel and fundamental features of reptile genome biology, provide insight into the regulation of snake venom, and broadly highlight the biological insight enabled by chromosome-level genome assemblies.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Giulia M Pasquesi
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Balan Ramesh
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Jeffery P Demuth
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Marc Tollis
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas 76402, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
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20
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Yazdi HP, Ellegren H. A Genetic Map of Ostrich Z Chromosome and the Role of Inversions in Avian Sex Chromosome Evolution. Genome Biol Evol 2018; 10:2049-2060. [PMID: 30099482 PMCID: PMC6105114 DOI: 10.1093/gbe/evy163] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 12/11/2022] Open
Abstract
Recombination arrest is a necessary step for the evolution of distinct sex chromosomes. Structural changes, such as inversions, may represent the mechanistic basis for recombination suppression and comparisons of the structural organization of chromosomes as given by chromosome-level assemblies offer the possibility to infer inversions across species at some detail. In birds, deduction of the process of sex chromosome evolution has been hampered by the lack of a validated chromosome-level assembly from a representative of one of the two basal clades of modern birds, Paleognathae. We therefore developed a high-density genetic linkage map of the ostrich Z chromosome and used this to correct an existing assembly, including correction of a large chimeric superscaffold and the order and orientation of other superscaffolds. We identified the pseudoautosomal region as a 52 Mb segment (≈60% of the Z chromosome) where recombination occurred in both sexes. By comparing the order and location of genes on the ostrich Z chromosome with that of six bird species from the other major clade of birds (Neognathae), and of reptilian outgroup species, 25 Z-linked inversions were inferred in the avian lineages. We defined Z chromosome organization in an early avian ancestor and identified inversions spanning the candidate sex-determining DMRT1 gene in this ancestor, which could potentially have triggered the onset of avian sex chromosome evolution. We conclude that avian sex chromosome evolution has been characterized by a complex process of probably both Z-linked and W-linked inversions (and/or other processes). This study illustrates the need for validated chromosome-level assemblies for inference of genome evolution.
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Affiliation(s)
- Homa Papoli Yazdi
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden
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21
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Sigeman H, Ponnikas S, Videvall E, Zhang H, Chauhan P, Naurin S, Hansson B. Insights into Avian Incomplete Dosage Compensation: Sex-Biased Gene Expression Coevolves with Sex Chromosome Degeneration in the Common Whitethroat. Genes (Basel) 2018; 9:genes9080373. [PMID: 30049999 PMCID: PMC6116046 DOI: 10.3390/genes9080373] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 02/02/2023] Open
Abstract
Non-recombining sex chromosomes (Y and W) accumulate deleterious mutations and degenerate. This poses a problem for the heterogametic sex (XY males; ZW females) because a single functional gene copy often implies less gene expression and a potential imbalance of crucial expression networks. Mammals counteract this by dosage compensation, resulting in equal sex chromosome expression in males and females, whereas birds show incomplete dosage compensation with significantly lower expression in females (ZW). Here, we study the evolution of Z and W sequence divergence and sex-specific gene expression in the common whitethroat (Sylvia communis), a species within the Sylvioidea clade where a neo-sex chromosome has been formed by a fusion between an autosome and the ancestral sex chromosome. In line with data from other birds, females had lower expression than males at the majority of sex-linked genes. Results from the neo-sex chromosome region showed that W gametologs have diverged functionally to a higher extent than their Z counterparts, and that the female-to-male expression ratio correlated negatively with the degree of functional divergence of these gametologs. We find it most likely that sex-linked genes are being suppressed in females as a response to W chromosome degradation, rather than that these genes experience relaxed selection, and thus diverge more, by having low female expression. Overall, our data of this unique avian neo-sex chromosome system suggest that incomplete dosage compensation evolves, at least partly, through gradual accumulation of deleterious mutations at the W chromosome and declining female gene expression.
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Affiliation(s)
- Hanna Sigeman
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Suvi Ponnikas
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Elin Videvall
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Hongkai Zhang
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Pallavi Chauhan
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Sara Naurin
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Bengt Hansson
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
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22
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Avia K, Lipinska AP, Mignerot L, Montecinos AE, Jamy M, Ahmed S, Valero M, Peters AF, Cock JM, Roze D, Coelho SM. Genetic Diversity in the UV Sex Chromosomes of the Brown Alga Ectocarpus. Genes (Basel) 2018; 9:E286. [PMID: 29882839 PMCID: PMC6027523 DOI: 10.3390/genes9060286] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 12/24/2022] Open
Abstract
Three types of sex chromosome system exist in nature: diploid XY and ZW systems and haploid UV systems. For many years, research has focused exclusively on XY and ZW systems, leaving UV chromosomes and haploid sex determination largely neglected. Here, we perform a detailed analysis of DNA sequence neutral diversity levels across the U and V sex chromosomes of the model brown alga Ectocarpus using a large population dataset. We show that the U and V non-recombining regions of the sex chromosomes (SDR) exhibit about half as much neutral diversity as the autosomes. This difference is consistent with the reduced effective population size of these regions compared with the rest of the genome, suggesting that the influence of additional factors such as background selection or selective sweeps is minimal. The pseudoautosomal region (PAR) of this UV system, in contrast, exhibited surprisingly high neutral diversity and there were several indications that genes in this region may be under balancing selection. The PAR of Ectocarpus is known to exhibit unusual genomic features and our results lay the foundation for further work aimed at understanding whether, and to what extent, these structural features underlie the high level of genetic diversity. Overall, this study fills a gap between available information on genetic diversity in XY/ZW systems and UV systems and significantly contributes to advancing our knowledge of the evolution of UV sex chromosomes.
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Affiliation(s)
- Komlan Avia
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, University of Paris VI, UC, UACH, UMI 3614, 29688 Roscoff, France.
| | - Agnieszka P Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
| | - Laure Mignerot
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
| | - Alejandro E Montecinos
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, University of Paris VI, UC, UACH, UMI 3614, 29688 Roscoff, France.
- Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
| | - Mahwash Jamy
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
| | - Sophia Ahmed
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
| | - Myriam Valero
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, University of Paris VI, UC, UACH, UMI 3614, 29688 Roscoff, France.
| | | | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
| | - Denis Roze
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, University of Paris VI, UC, UACH, UMI 3614, 29688 Roscoff, France.
| | - Susana M Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France.
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23
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Irwin DE. Sex chromosomes and speciation in birds and other ZW systems. Mol Ecol 2018; 27:3831-3851. [PMID: 29443419 DOI: 10.1111/mec.14537] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 02/03/2018] [Accepted: 02/06/2018] [Indexed: 01/01/2023]
Abstract
Theory and empirical patterns suggest a disproportionate role for sex chromosomes in evolution and speciation. Focusing on ZW sex determination (females ZW, males ZZ; the system in birds, many snakes, and lepidopterans), I review how evolutionary dynamics are expected to differ between the Z, W and the autosomes, discuss how these differences may lead to a greater role of the sex chromosomes in speciation and use data from birds to compare relative evolutionary rates of sex chromosomes and autosomes. Neutral mutations, partially or completely recessive beneficial mutations, and deleterious mutations under many conditions are expected to accumulate faster on the Z than on autosomes. Sexually antagonistic polymorphisms are expected to arise on the Z, raising the possibility of the spread of preference alleles. The faster accumulation of many types of mutations and the potential for complex evolutionary dynamics of sexually antagonistic traits and preferences contribute to a role for the Z chromosome in speciation. A quantitative comparison among a wide variety of bird species shows that the Z tends to have less within-population diversity and greater between-species differentiation than the autosomes, likely due to both adaptive evolution and a greater rate of fixation of deleterious alleles. The W chromosome also shows strong potential to be involved in speciation, in part because of its co-inheritance with the mitochondrial genome. While theory and empirical evidence suggest a disproportionate role for sex chromosomes in speciation, the importance of sex chromosomes is moderated by their small size compared to the whole genome.
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Affiliation(s)
- Darren E Irwin
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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24
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Kawakami T, Mugal CF, Suh A, Nater A, Burri R, Smeds L, Ellegren H. Whole-genome patterns of linkage disequilibrium across flycatcher populations clarify the causes and consequences of fine-scale recombination rate variation in birds. Mol Ecol 2017; 26:4158-4172. [DOI: 10.1111/mec.14197] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/02/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Takeshi Kawakami
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - Carina F. Mugal
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Alexander Suh
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Alexander Nater
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Zürich Switzerland
| | - Reto Burri
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Population Ecology; Friedrich Schiller University Jena; Jena Germany
| | - Linnéa Smeds
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
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25
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Tomaszkiewicz M, Medvedev P, Makova KD. Y and W Chromosome Assemblies: Approaches and Discoveries. Trends Genet 2017; 33:266-282. [DOI: 10.1016/j.tig.2017.01.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/05/2016] [Accepted: 01/24/2017] [Indexed: 01/19/2023]
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26
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Dutoit L, Burri R, Nater A, Mugal CF, Ellegren H. Genomic distribution and estimation of nucleotide diversity in natural populations: perspectives from the collared flycatcher (Ficedula albicollis) genome. Mol Ecol Resour 2016; 17:586-597. [DOI: 10.1111/1755-0998.12602] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 09/02/2016] [Accepted: 09/19/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Ludovic Dutoit
- Department of Evolutionary Biology; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - Reto Burri
- Department of Evolutionary Biology; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - Alexander Nater
- Department of Evolutionary Biology; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - Carina F. Mugal
- Department of Evolutionary Biology; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
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27
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Abstract
Genetic polymorphism varies among species and within genomes, and has important implications for the evolution and conservation of species. The determinants of this variation have been poorly understood, but population genomic data from a wide range of organisms now make it possible to delineate the underlying evolutionary processes, notably how variation in the effective population size (Ne) governs genetic diversity. Comparative population genomics is on its way to providing a solution to 'Lewontin's paradox' - the discrepancy between the many orders of magnitude of variation in population size and the much narrower distribution of diversity levels. It seems that linked selection plays an important part both in the overall genetic diversity of a species and in the variation in diversity within the genome. Genetic diversity also seems to be predictable from the life history of a species.
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28
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Mignerot L, Coelho SM. The origin and evolution of the sexes: Novel insights from a distant eukaryotic linage. C R Biol 2016; 339:252-7. [PMID: 27236828 DOI: 10.1016/j.crvi.2016.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 04/14/2016] [Accepted: 04/14/2016] [Indexed: 10/21/2022]
Abstract
Sexual reproduction is an extraordinarily widespread phenomenon that assures the production of new genetic combinations in nearly all eukaryotic lineages. Although the core features of sexual reproduction (meiosis and syngamy) are highly conserved, the control mechanisms that determine whether an individual is male or female are remarkably labile across eukaryotes. In genetically controlled sexual systems, gender is determined by sex chromosomes, which have emerged independently and repeatedly during evolution. Sex chromosomes have been studied in only a handful of classical model organism, and empirical knowledge on the origin and evolution of the sexes is still surprisingly incomplete. With the advent of new generation sequencing, the taxonomic breadth of model systems has been rapidly expanding, bringing new ideas and fresh views on this fundamental aspect of biology. This mini-review provides a quick state of the art of how the remarkable richness of the sexual characteristics of the brown algae is helping to increase our knowledge about the evolution of sex determination.
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Affiliation(s)
- Laure Mignerot
- CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Sorbonne Universités, UPMC (Université Paris-6, station biologique de Roscoff, place George-Teissier, CS 90074, 29688 Roscoff cedex, France
| | - Susana M Coelho
- CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Sorbonne Universités, UPMC (Université Paris-6, station biologique de Roscoff, place George-Teissier, CS 90074, 29688 Roscoff cedex, France.
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29
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Smeds L, Mugal CF, Qvarnström A, Ellegren H. High-Resolution Mapping of Crossover and Non-crossover Recombination Events by Whole-Genome Re-sequencing of an Avian Pedigree. PLoS Genet 2016; 12:e1006044. [PMID: 27219623 PMCID: PMC4878770 DOI: 10.1371/journal.pgen.1006044] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 04/19/2016] [Indexed: 01/04/2023] Open
Abstract
Recombination is an engine of genetic diversity and therefore constitutes a key process in evolutionary biology and genetics. While the outcome of crossover recombination can readily be detected as shuffled alleles by following the inheritance of markers in pedigreed families, the more precise location of both crossover and non-crossover recombination events has been difficult to pinpoint. As a consequence, we lack a detailed portrait of the recombination landscape for most organisms and knowledge on how this landscape impacts on sequence evolution at a local scale. To localize recombination events with high resolution in an avian system, we performed whole-genome re-sequencing at high coverage of a complete three-generation collared flycatcher pedigree. We identified 325 crossovers at a median resolution of 1.4 kb, with 86% of the events localized to <10 kb intervals. Observed crossover rates were in excellent agreement with data from linkage mapping, were 52% higher in male (3.56 cM/Mb) than in female meiosis (2.28 cM/Mb), and increased towards chromosome ends in male but not female meiosis. Crossover events were non-randomly distributed in the genome with several distinct hot-spots and a concentration to genic regions, with the highest density in promoters and CpG islands. We further identified 267 non-crossovers, whose location was significantly associated with crossover locations. We detected a significant transmission bias (0.18) in favour of 'strong' (G, C) over 'weak' (A, T) alleles at non-crossover events, providing direct evidence for the process of GC-biased gene conversion in an avian system. The approach taken in this study should be applicable to any species and would thereby help to provide a more comprehensive portray of the recombination landscape across organism groups.
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Affiliation(s)
- Linnéa Smeds
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Carina F. Mugal
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Anna Qvarnström
- Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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30
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Mammalian X homolog acts as sex chromosome in lacertid lizards. Heredity (Edinb) 2016; 117:8-13. [PMID: 26980341 DOI: 10.1038/hdy.2016.18] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/16/2015] [Accepted: 02/02/2016] [Indexed: 01/13/2023] Open
Abstract
Among amniotes, squamate reptiles are especially variable in their mechanisms of sex determination; however, based largely on cytogenetic data, some lineages possess highly evolutionary stable sex chromosomes. The still very limited knowledge of the genetic content of squamate sex chromosomes precludes a reliable reconstruction of the evolutionary history of sex determination in this group and consequently in all amniotes. Female heterogamety with a degenerated W chromosome typifies the lizards of the family Lacertidae, the widely distributed Old World clade including several hundreds of species. From the liver transcriptome of the lacertid Takydromus sexlineatus female, we selected candidates for Z-specific genes as the loci lacking single-nucleotide polymorphisms. We validated the candidate genes through the comparison of the copy numbers in the female and male genomes of T. sexlineatus and another lacertid species, Lacerta agilis, by quantitative PCR that also proved to be a reliable technique for the molecular sexing of the studied species. We suggest that this novel approach is effective for the detection of Z-specific and X-specific genes in lineages with degenerated W, respectively Y chromosomes. The analyzed gene content of the Z chromosome revealed that lacertid sex chromosomes are not homologous with those of other reptiles including birds, but instead the genes have orthologs in the X-conserved region shared by viviparous mammals. It is possible that this part of the vertebrate genome was independently co-opted for the function of sex chromosomes in viviparous mammals and lacertids because of its content of genes involved in gonad differentiation.
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31
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Raudsepp T, Chowdhary BP. The Eutherian Pseudoautosomal Region. Cytogenet Genome Res 2016; 147:81-94. [PMID: 26730606 DOI: 10.1159/000443157] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2015] [Indexed: 11/19/2022] Open
Abstract
The pseudoautosomal region (PAR) is a unique segment of sequence homology between differentiated sex chromosomes where recombination occurs during meiosis. Molecular and functional properties of the PAR are distinctive from the autosomes and the remaining regions of the sex chromosomes. These include a higher rate of recombination than genome average, bias towards GC-substitutions and increased interindividual nucleotide divergence and mutations. As yet, the PAR has been physically demarcated in only 28 eutherian species representing 6 mammalian orders. Murid rodents have the smallest, gene-poorest and most diverged PARs. Other eutherian PARs are largely homologous but differ in size and gene content, being the smallest in equids and human/simian primates and much larger in other eutherians. Because pseudoautosomal genes escape X inactivation, their dosage changes with sex chromosome aneuploidies, whereas phenotypic effects of the latter depend on the size and gene content of the PAR. Thus, X monosomy is more viable in mice, humans and horses than in species with larger PARs. Presently, little is known about the functions of PAR genes in individual species, though human studies suggest their involvement in early embryonic development. The PAR is, thus, of evolutionary, genetic and biomedical significance and a 'research hotspot' in eutherian genomes.
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Affiliation(s)
- Terje Raudsepp
- Department of Veterinary Integrative Biosciences, CVM, Texas A&M University, College Station, Tex., USA
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32
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Singhal S, Leffler EM, Sannareddy K, Turner I, Venn O, Hooper DM, Strand AI, Li Q, Raney B, Balakrishnan CN, Griffith SC, McVean G, Przeworski M. Stable recombination hotspots in birds. Science 2015; 350:928-32. [PMID: 26586757 PMCID: PMC4864528 DOI: 10.1126/science.aad0843] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The DNA-binding protein PRDM9 has a critical role in specifying meiotic recombination hotspots in mice and apes, but it appears to be absent from other vertebrate species, including birds. To study the evolution and determinants of recombination in species lacking the gene that encodes PRDM9, we inferred fine-scale genetic maps from population resequencing data for two bird species: the zebra finch, Taeniopygia guttata, and the long-tailed finch, Poephila acuticauda. We found that both species have recombination hotspots, which are enriched near functional genomic elements. Unlike in mice and apes, most hotspots are shared between the two species, and their conservation seems to extend over tens of millions of years. These observations suggest that in the absence of PRDM9, recombination targets functional features that both enable access to the genome and constrain its evolution.
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Affiliation(s)
- Sonal Singhal
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA. Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ellen M Leffler
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Keerthi Sannareddy
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Isaac Turner
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Oliver Venn
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Daniel M Hooper
- Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637, USA
| | - Alva I Strand
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Qiye Li
- China National Genebank, BGI-Shenzhen, Shenzhen 518083, China
| | - Brian Raney
- Center for Biomolecular Science and Engineering, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| | | | - Simon C Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Gil McVean
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Molly Przeworski
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA. Department of Systems Biology, Columbia University, New York, NY 10032, USA.
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33
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Luthringer R, Lipinska AP, Roze D, Cormier A, Macaisne N, Peters AF, Cock JM, Coelho SM. The Pseudoautosomal Regions of the U/V Sex Chromosomes of the Brown Alga Ectocarpus Exhibit Unusual Features. Mol Biol Evol 2015; 32:2973-85. [PMID: 26248564 PMCID: PMC4610043 DOI: 10.1093/molbev/msv173] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The recombining regions of sex chromosomes (pseudoautosomal regions, PARs) are predicted to exhibit unusual features due to their being genetically linked to the nonrecombining, sex-determining region. This phenomenon is expected to occur in both diploid (XY, ZW) and haploid (UV) sexual systems, with slightly different consequences for UV sexual systems because of the absence of masking during the haploid phase (when sex is expressed) and because there is no homozygous sex in these systems. Despite a considerable amount of theoretical work on PAR genetics and evolution, these genomic regions have remained poorly characterized empirically. We show here that although the PARs of the U/V sex chromosomes of the brown alga Ectocarpus recombine at a similar rate to autosomal regions of the genome, they exhibit many genomic features typical of nonrecombining regions. The PARs were enriched in clusters of genes that are preferentially, and often exclusively, expressed during the sporophyte generation of the life cycle, and many of these genes appear to have evolved since the Ectocarpales diverged from other brown algal lineages. A modeling-based approach was used to investigate possible evolutionary mechanisms underlying this enrichment in sporophyte-biased genes. Our results are consistent with the evolution of the PAR in haploid systems being influenced by differential selection pressures in males and females acting on alleles that are advantageous during the sporophyte generation of the life cycle.
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Affiliation(s)
- Rémy Luthringer
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Agnieszka P Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Denis Roze
- UMI 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, PUCCh, UACH, Station Biologique de Roscoff, Roscoff, France
| | - Alexandre Cormier
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Nicolas Macaisne
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | | | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Susana M Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
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34
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Schmid M, Smith J, Burt DW, Aken BL, Antin PB, Archibald AL, Ashwell C, Blackshear PJ, Boschiero C, Brown CT, Burgess SC, Cheng HH, Chow W, Coble DJ, Cooksey A, Crooijmans RPMA, Damas J, Davis RVN, de Koning DJ, Delany ME, Derrien T, Desta TT, Dunn IC, Dunn M, Ellegren H, Eöry L, Erb I, Farré M, Fasold M, Fleming D, Flicek P, Fowler KE, Frésard L, Froman DP, Garceau V, Gardner PP, Gheyas AA, Griffin DK, Groenen MAM, Haaf T, Hanotte O, Hart A, Häsler J, Hedges SB, Hertel J, Howe K, Hubbard A, Hume DA, Kaiser P, Kedra D, Kemp SJ, Klopp C, Kniel KE, Kuo R, Lagarrigue S, Lamont SJ, Larkin DM, Lawal RA, Markland SM, McCarthy F, McCormack HA, McPherson MC, Motegi A, Muljo SA, Münsterberg A, Nag R, Nanda I, Neuberger M, Nitsche A, Notredame C, Noyes H, O'Connor R, O'Hare EA, Oler AJ, Ommeh SC, Pais H, Persia M, Pitel F, Preeyanon L, Prieto Barja P, Pritchett EM, Rhoads DD, Robinson CM, Romanov MN, Rothschild M, Roux PF, Schmidt CJ, Schneider AS, Schwartz MG, Searle SM, Skinner MA, Smith CA, Stadler PF, Steeves TE, Steinlein C, Sun L, Takata M, Ulitsky I, Wang Q, Wang Y, Warren WC, Wood JMD, Wragg D, Zhou H. Third Report on Chicken Genes and Chromosomes 2015. Cytogenet Genome Res 2015; 145:78-179. [PMID: 26282327 PMCID: PMC5120589 DOI: 10.1159/000430927] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Michael Schmid
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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Smeds L, Warmuth V, Bolivar P, Uebbing S, Burri R, Suh A, Nater A, Bureš S, Garamszegi LZ, Hogner S, Moreno J, Qvarnström A, Ružić M, Sæther SA, Sætre GP, Török J, Ellegren H. Evolutionary analysis of the female-specific avian W chromosome. Nat Commun 2015; 6:7330. [PMID: 26040272 PMCID: PMC4468903 DOI: 10.1038/ncomms8330] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/28/2015] [Indexed: 02/07/2023] Open
Abstract
The typically repetitive nature of the sex-limited chromosome means that it is often excluded from or poorly covered in genome assemblies, hindering studies of evolutionary and population genomic processes in non-recombining chromosomes. Here, we present a draft assembly of the non-recombining region of the collared flycatcher W chromosome, containing 46 genes without evidence of female-specific functional differentiation. Survival of genes during W chromosome degeneration has been highly non-random and expression data suggest that this can be attributed to selection for maintaining gene dose and ancestral expression levels of essential genes. Re-sequencing of large population samples revealed dramatically reduced levels of within-species diversity and elevated rates of between-species differentiation (lineage sorting), consistent with low effective population size. Concordance between W chromosome and mitochondrial DNA phylogenetic trees demonstrates evolutionary stable matrilineal inheritance of this nuclear–cytonuclear pair of chromosomes. Our results show both commonalities and differences between W chromosome and Y chromosome evolution. The evolution of non-recombining chromosomes is poorly understood. Here, the authors sequence the collared flycatcher female-specific W chromosome and show nonrandom survival of genes during W chromosome degeneration which is due to selection for maintaining gene dose and expression levels of essential genes.
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Affiliation(s)
- Linnéa Smeds
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Vera Warmuth
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Paulina Bolivar
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Severin Uebbing
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Reto Burri
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Alexander Suh
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Alexander Nater
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 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
- 1] Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway [2] 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
- 1] Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway [2] 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, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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