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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Zhu Z, Younas L, Zhou Q. Evolution and regulation of animal sex chromosomes. Nat Rev Genet 2024:10.1038/s41576-024-00757-3. [PMID: 39026082 DOI: 10.1038/s41576-024-00757-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
Animal sex chromosomes typically carry the upstream sex-determining gene that triggers testis or ovary development and, in some species, are regulated by global dosage compensation in response to functional decay of the Y chromosome. Despite the importance of these pathways, they exhibit striking differences across species, raising fundamental questions regarding the mechanisms underlying their evolutionary turnover. Recent studies of non-model organisms, including insects, reptiles and teleosts, have yielded a broad view of the diversity of sex chromosomes that challenges established theories. Moreover, continued studies in model organisms with recently developed technologies have characterized the dynamics of sex determination and dosage compensation in three-dimensional nuclear space and at single-cell resolution. Here, we synthesize recent insights into sex chromosomes from a variety of species to review their evolutionary dynamics with respect to the canonical model, as well as their diverse mechanisms of regulation.
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Affiliation(s)
- Zexian Zhu
- Evolutionary and Organismal Biology Research Center and Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lubna Younas
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Qi Zhou
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China.
- State Key Laboratory of Transvascular Implantation Devices, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
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3
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Castellanos MDP, Wickramasinghe CD, Betrán E. The roles of gene duplications in the dynamics of evolutionary conflicts. Proc Biol Sci 2024; 291:20240555. [PMID: 38865605 DOI: 10.1098/rspb.2024.0555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 04/02/2024] [Indexed: 06/14/2024] Open
Abstract
Evolutionary conflicts occur when there is antagonistic selection between different individuals of the same or different species, life stages or between levels of biological organization. Remarkably, conflicts can occur within species or within genomes. In the dynamics of evolutionary conflicts, gene duplications can play a major role because they can bring very specific changes to the genome: changes in protein dose, the generation of novel paralogues with different functions or expression patterns or the evolution of small antisense RNAs. As we describe here, by having those effects, gene duplication might spark evolutionary conflict or fuel arms race dynamics that takes place during conflicts. Interestingly, gene duplication can also contribute to the resolution of a within-locus evolutionary conflict by partitioning the functions of the gene that is under an evolutionary trade-off. In this review, we focus on intraspecific conflicts, including sexual conflict and illustrate the various roles of gene duplications with a compilation of examples. These examples reveal the level of complexity and the differences in the patterns of gene duplications within genomes under different conflicts. These examples also reveal the gene ontologies involved in conflict and the genomic location of the elements of the conflict. The examples provide a blueprint for the direct study of these conflicts or the exploration of the presence of similar conflicts in other lineages.
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Affiliation(s)
| | | | - Esther Betrán
- Department of Biology, University of Texas at Arlington , Arlington, TX 76019, USA
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4
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Kitano J, Ansai S, Takehana Y, Yamamoto Y. Diversity and Convergence of Sex-Determination Mechanisms in Teleost Fish. Annu Rev Anim Biosci 2024; 12:233-259. [PMID: 37863090 DOI: 10.1146/annurev-animal-021122-113935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Sexual reproduction is prevalent across diverse taxa. However, sex-determination mechanisms are so diverse that even closely related species often differ in sex-determination systems. Teleost fish is a taxonomic group with frequent turnovers of sex-determining mechanisms and thus provides us with great opportunities to investigate the molecular and evolutionary mechanisms underlying the turnover of sex-determining systems. Here, we compile recent studies on the diversity of sex-determination mechanisms in fish. We demonstrate that genes in the TGF-β signaling pathway are frequently used for master sex-determining (MSD) genes. MSD genes arise via two main mechanisms, duplication-and-transposition and allelic mutations, with a few exceptions. We also demonstrate that temperature influences sex determination in many fish species, even those with sex chromosomes, with higher temperatures inducing differentiation into males in most cases. Finally, we review theoretical models for the turnover of sex-determining mechanisms and discuss what questions remain elusive.
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Affiliation(s)
- Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan;
| | - Satoshi Ansai
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan;
| | - Yusuke Takehana
- Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan;
| | - Yoji Yamamoto
- Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Tokyo, Japan;
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5
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Behrens KA, Zimmermann H, Blažek R, Reichard M, Koblmüller S, Kocher TD. Turnover of sex chromosomes in the Lake Tanganyika cichlid tribe Tropheini (Teleostei: Cichlidae). Sci Rep 2024; 14:2471. [PMID: 38291228 PMCID: PMC10828463 DOI: 10.1038/s41598-024-53021-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 01/25/2024] [Indexed: 02/01/2024] Open
Abstract
Sex chromosome replacement is frequent in many vertebrate clades, including fish, frogs, and lizards. In order to understand the mechanisms responsible for sex chromosome turnover and the early stages of sex chromosome divergence, it is necessary to study lineages with recently evolved sex chromosomes. Here we examine sex chromosome evolution in a group of African cichlid fishes (tribe Tropheini) which began to diverge from one another less than 4 MYA. We have evidence for a previously unknown sex chromosome system, and preliminary indications of several additional systems not previously reported in this group. We find a high frequency of sex chromosome turnover and estimate a minimum of 14 turnovers in this tribe. We date the origin of the most common sex determining system in this tribe (XY-LG5/19) near the base of one of two major sub-clades of this tribe, about 3.4 MY ago. Finally, we observe variation in the size of one sex-determining region that suggests independent evolution of evolutionary strata in species with a shared sex-determination system. Our results illuminate the rapid rate of sex chromosome turnover in the tribe Tropheini and set the stage for further studies of the dynamics of sex chromosome evolution in this group.
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Affiliation(s)
- Kristen A Behrens
- Department of Biology, University of Maryland, College Park, MD, 20742, USA.
| | - Holger Zimmermann
- Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 603 00, Brno, Czech Republic
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Radim Blažek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 603 00, Brno, Czech Republic
| | - Martin Reichard
- Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 603 00, Brno, Czech Republic
- Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland
| | - Stephan Koblmüller
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Thomas D Kocher
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
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6
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Cumer T, Machado AP, San-Jose LM, Ducrest AL, Simon C, Roulin A, Goudet J. The genomic architecture of continuous plumage colour variation in the European barn owl ( Tyto alba). Proc Biol Sci 2024; 291:20231995. [PMID: 38196365 PMCID: PMC10777144 DOI: 10.1098/rspb.2023.1995] [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: 09/06/2023] [Accepted: 11/30/2023] [Indexed: 01/11/2024] Open
Abstract
The maintenance of colour variation in wild populations has long fascinated evolutionary biologists, although most studies have focused on discrete traits exhibiting rather simple inheritance patterns and genetic architectures. However, the study of continuous colour traits and their potentially oligo- or polygenic genetic bases remains rare in wild populations. We studied the genetics of the continuously varying white-to-rufous plumage coloration of the European barn owl (Tyto alba) using a genome-wide association approach on the whole-genome data of 75 individuals. We confirmed a mutation at the melanocortin-1-receptor gene (MC1R) is involved in the coloration and identified two new regions, located in super-scaffolds 9 and 42. The combination of the three regions explains most of the colour variation (80.37%, 95% credible interval 58.45-100%). One discovered region, located in the sex chromosome, differs between the most extreme colorations in owls sharing a specific MC1R genotype. This region may play a role in the colour sex dimorphism of this species, possibly in interaction with the autosomal MC1R. We thus provide insights into the genetic architecture of continuous colour variation, pointing to an oligogenic basis with potential epistatic effects among loci that should aid future studies understanding how continuous colour variation is maintained in nature.
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Affiliation(s)
- Tristan Cumer
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Ana Paula Machado
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Luis M. San-Jose
- Laboratoire Évolution and Diversité Biologique, UMR 5174, CNRS, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Anne-Lyse Ducrest
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Céline Simon
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Jérôme Goudet
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
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7
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Mora P, Hospodářská M, Voleníková AC, Koutecký P, Štundlová J, Dalíková M, Walters JR, Nguyen P. Sex-biased gene content is associated with sex chromosome turnover in Danaini butterflies. Mol Ecol 2024:e17256. [PMID: 38180347 DOI: 10.1111/mec.17256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/01/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024]
Abstract
Sex chromosomes play an outsized role in adaptation and speciation, and thus deserve particular attention in evolutionary genomics. In particular, fusions between sex chromosomes and autosomes can produce neo-sex chromosomes, which offer important insights into the evolutionary dynamics of sex chromosomes. Here, we investigate the evolutionary origin of the previously reported Danaus neo-sex chromosome within the tribe Danaini. We assembled and annotated genomes of Tirumala septentrionis (subtribe Danaina), Ideopsis similis (Amaurina), Idea leuconoe (Euploeina) and Lycorea halia (Itunina) and identified their Z-linked scaffolds. We found that the Danaus neo-sex chromosome resulting from the fusion between a Z chromosome and an autosome corresponding to the Melitaea cinxia chromosome (McChr) 21 arose in a common ancestor of Danaina, Amaurina and Euploina. We also identified two additional fusions as the W chromosome further fused with the synteny block McChr31 in I. similis and independent fusion occurred between ancestral Z chromosome and McChr12 in L. halia. We further tested a possible role of sexually antagonistic selection in sex chromosome turnover by analysing the genomic distribution of sex-biased genes in I. leuconoe and L. halia. The autosomes corresponding to McChr21 and McChr31 involved in the fusions are significantly enriched in female- and male-biased genes, respectively, which could have hypothetically facilitated fixation of the neo-sex chromosomes. This suggests a role of sexual antagonism in sex chromosome turnover in Lepidoptera. The neo-Z chromosomes of both I. leuconoe and L. halia appear fully compensated in somatic tissues, but the extent of dosage compensation for the ancestral Z varies across tissues and species.
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Affiliation(s)
- Pablo Mora
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Monika Hospodářská
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | | | - Petr Koutecký
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Jana Štundlová
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Martina Dalíková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
| | - James R Walters
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
| | - Petr Nguyen
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
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8
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Smith SH, Hsiung K, Böhne A. Evaluating the role of sexual antagonism in the evolution of sex chromosomes: new data from fish. Curr Opin Genet Dev 2023; 81:102078. [PMID: 37379742 DOI: 10.1016/j.gde.2023.102078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/30/2023]
Abstract
The recent increase in available molecular and genomic data for diverse taxa helps to shed new light on long-standing theories. Research into sex chromosome evolution has particularly benefited from a growing number of studies of fish, motivated by their highly diverse mechanisms of sex determination. Sexual antagonism is regularly cited as an influential force in sex chromosome emergence; however, this so far proves difficult to demonstrate. In this review, we highlight recent developments in the investigation of sexual antagonism in sex chromosome research in fish. We find strong emphasis placed on study-organism specific genomic features and patterns of recombination, rather than evidence for a comprehensive role of sexual antagonism. In this light, we discuss the alternative models of sex chromosome evolution. We conclude that fish represents a key resource for further research, provided attention is given to species-specific effects while simultaneously integrating comparative studies across taxa for a vital and comprehensive understanding of sex chromosome evolution and investigation of proposed models.
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Affiliation(s)
- Sophie Helen Smith
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany. https://twitter.com/@shg_smith
| | - Kevin Hsiung
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany. https://twitter.com/@KevinKHsiung
| | - Astrid Böhne
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany.
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9
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Charlesworth D. Why and how do Y chromosome stop recombining? J Evol Biol 2023; 36:632-636. [PMID: 36683363 DOI: 10.1111/jeb.14137] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/21/2022] [Accepted: 11/24/2022] [Indexed: 01/24/2023]
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10
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Marajó L, Viana PF, Ferreira AMV, Py-Daniel LHR, Cioffi MDB, Sember A, Feldberg E. Chromosomal rearrangements and the first indication of an ♀X 1 X 1 X 2 X 2 /♂X 1 X 2 Y sex chromosome system in Rineloricaria fishes (Teleostei: Siluriformes). JOURNAL OF FISH BIOLOGY 2023; 102:443-454. [PMID: 36427042 DOI: 10.1111/jfb.15275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
Rineloricaria is the most diverse genus within the freshwater fish subfamily Loricariinae, and it is widely distributed in the Neotropical region. Despite limited cytogenetic data, records from southern and south-eastern Brazil suggest a high rate of chromosomal rearrangements in this genus, mirrored in remarkable inter- and intraspecific karyotype variability. In the present work, we investigated the karyotype features of Rineloricaria teffeana, an endemic representative from northern Brazil, using both conventional and molecular cytogenetic techniques. We revealed different diploid chromosome numbers (2n) between sexes (33♂/34♀), which suggests the presence of an ♀X1 X1 X2 X2 /♂X1 X2 Y multiple sex chromosome system. The male-limited Y chromosome was the largest and the only biarmed element in the karyotype, implying Y-autosome fusion as the most probable mechanism behind its origination. C-banding revealed low amounts of constitutive heterochromatin, mostly confined to the (peri)centromeric regions of most chromosomes (including the X2 and the Y) but also occupying the distal regions of a few chromosomal pairs. The chromosomal localization of the 18S ribosomal DNA (rDNA) clusters revealed a single site on chromosome pair 4, which was adjacent to the 5S rDNA cluster. Additional 5S rDNA loci were present on the autosome pair 8, X1 chromosome, and in the presumed fusion point on the Y chromosome. The probe for telomeric repeat motif (TTAGGG)n revealed signals of variable intensities at the ends of all chromosomes except for the Y chromosome, where no detectable signals were evidenced. Male-to-female comparative genomic hybridization revealed no sex-specific or sex-biased repetitive DNA accumulations, suggesting a presumably low level of neo-Y chromosome differentiation. We provide evidence that rDNA sites might have played a role in the formation of this putative multiple sex chromosome system and that chromosome fusions originate through different mechanisms among different Rineloricaria species.
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Affiliation(s)
- Leandro Marajó
- Laboratório de Genética Animal, Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Patrik Ferreira Viana
- Laboratório de Genética Animal, Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Alex Matheus Viana Ferreira
- Laboratório de Genética Animal, Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Lúcia Helena Rapp Py-Daniel
- Coleção de Peixes, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Marcelo de Bello Cioffi
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Libechov, Czech Republic
| | - Eliana Feldberg
- Laboratório de Genética Animal, Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
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11
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Long X, Charlesworth D, Qi J, Wu R, Chen M, Wang Z, Xu L, Fu H, Zhang X, Chen X, He L, Zheng L, Huang Z, Zhou Q. Independent Evolution of Sex Chromosomes and Male Pregnancy-Related Genes in Two Seahorse Species. Mol Biol Evol 2022; 40:6964685. [PMID: 36578180 PMCID: PMC9851323 DOI: 10.1093/molbev/msac279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/14/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022] Open
Abstract
Unlike birds and mammals, many teleosts have homomorphic sex chromosomes, and changes in the chromosome carrying the sex-determining locus, termed "turnovers", are common. Recent turnovers allow studies of several interesting questions. One question is whether the new sex-determining regions evolve to become completely non-recombining, and if so, how and why. Another is whether (as predicted) evolutionary changes that benefit one sex accumulate in the newly sex-linked region. To study these questions, we analyzed the genome sequences of two seahorse species of the Syngnathidae, a fish group in which many species evolved a unique structure, the male brood pouch. We find that both seahorse species have XY sex chromosome systems, but their sex chromosome pairs are not homologs, implying that at least one turnover event has occurred. The Y-linked regions occupy 63.9% and 95.1% of the entire sex chromosome of the two species and do not exhibit extensive sequence divergence with their X-linked homologs. We find evidence for occasional recombination between the extant sex chromosomes that may account for their homomorphism. We argue that these Y-linked regions did not evolve by recombination suppression after the turnover, but by the ancestral nature of the low crossover rates in these chromosome regions. With such an ancestral crossover landscape, a turnover can instantly create an extensive Y-linked region. Finally, we test for adaptive evolution of male pouch-related genes after they became Y-linked in the seahorse.
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Affiliation(s)
- Xin Long
- MOE Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China,Research Center for Intelligent Computing Platforms, Zhejiang Lab, Hangzhou 311100, China
| | - Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3LF, UK
| | - Jianfei Qi
- Department of Aquaculture, Fisheries Research Institute of Fujian, Xiamen 361013, China
| | - Ruiqiong Wu
- Fujian Key Laboratory of Developmental and Neural Biology & Southern Center for Biomedical Research, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, China
| | - Meiling Chen
- Fujian Key Laboratory of Developmental and Neural Biology & Southern Center for Biomedical Research, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, China
| | - Zongji Wang
- MOE Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Luohao Xu
- MOE Key Laboratory of Freshwater Fish Reproduction and Development, Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Honggao Fu
- Fujian Key Laboratory of Developmental and Neural Biology & Southern Center for Biomedical Research, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, China
| | - Xueping Zhang
- Fujian Key Laboratory of Developmental and Neural Biology & Southern Center for Biomedical Research, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, China
| | - Xinxin Chen
- Department of Aquaculture, Fisheries Research Institute of Fujian, Xiamen 361013, China
| | - Libin He
- Department of Aquaculture, Fisheries Research Institute of Fujian, Xiamen 361013, China
| | | | | | - Qi Zhou
- Corresponding authors: E-mails: ; ;
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12
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Qiu S, Yong L, Wilson A, Croft DP, Graham C, Charlesworth D. Partial sex linkage and linkage disequilibrium on the guppy sex chromosome. Mol Ecol 2022; 31:5524-5537. [PMID: 36005298 PMCID: PMC9826361 DOI: 10.1111/mec.16674] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/01/2022] [Accepted: 08/09/2022] [Indexed: 01/11/2023]
Abstract
The guppy Y chromosome has been considered a model system for the evolution of suppressed recombination between sex chromosomes, and it has been proposed that complete sex-linkage has evolved across about 3 Mb surrounding this fish's sex-determining locus, followed by recombination suppression across a further 7 Mb of the 23 Mb XY pair, forming younger "evolutionary strata". Sequences of the guppy genome show that Y is very similar to the X chromosome. Knowing which parts of the Y are completely nonrecombining, and whether there is indeed a large completely nonrecombining region, are important for understanding its evolution. Here, we describe analyses of PoolSeq data in samples from within multiple natural populations from Trinidad, yielding new results that support previous evidence for occasional recombination between the guppy Y and X. We detected recent demographic changes, notably that downstream populations have higher synonymous site diversity than upstream ones and other expected signals of bottlenecks. We detected evidence of associations between sequence variants and the sex-determining locus, rather than divergence under a complete lack of recombination. Although recombination is infrequent, it is frequent enough that associations with SNPs can suggest the region in which the sex-determining locus must be located. Diversity is elevated across a physically large region of the sex chromosome, conforming to predictions for a genome region with infrequent recombination that carries one or more sexually antagonistic polymorphisms. However, no consistently male-specific variants were found, supporting the suggestion that any completely sex-linked region may be very small.
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Affiliation(s)
- Suo Qiu
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Lengxob Yong
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterPenrynUK,Marine Resources Research InstituteSouth Carolina Department of Natural ResourcesCharlestonSouth CarolinaUSA
| | - Alastair Wilson
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterPenrynUK
| | - Darren P. Croft
- Centre for Research in Animal Behaviour, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Chay Graham
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghUK
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Berdan EL, Flatt T, Kozak GM, Lotterhos KE, Wielstra B. Genomic architecture of supergenes: connecting form and function. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210192. [PMID: 35694757 PMCID: PMC9189501 DOI: 10.1098/rstb.2021.0192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Supergenes are tightly linked sets of loci that are inherited together and control complex phenotypes. While classical supergenes-governing traits such as wing patterns in Heliconius butterflies or heterostyly in Primula-have been studied since the Modern Synthesis, we still understand very little about how they evolve and persist in nature. The genetic architecture of supergenes is a critical factor affecting their evolutionary fate, as it can change key parameters such as recombination rate and effective population size, potentially redirecting molecular evolution of the supergene in addition to the surrounding genomic region. To understand supergene evolution, we must link genomic architecture with evolutionary patterns and processes. This is now becoming possible with recent advances in sequencing technology and powerful forward computer simulations. The present theme issue brings together theoretical and empirical papers, as well as opinion and synthesis papers, which showcase the architectural diversity of supergenes and connect this to critical processes in supergene evolution, such as polymorphism maintenance and mutation accumulation. Here, we summarize those insights to highlight new ideas and methods that illuminate the path forward for the study of supergenes in nature. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
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Affiliation(s)
- Emma L Berdan
- Institute of Biology Leiden, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands.,Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, The Netherlands.,Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, 45296 Strömstad, Sweden
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Genevieve M Kozak
- Department of Biology, University of Massachusetts Dartmouth, 285 Old Westport Road, MA 02747, USA
| | - Katie E Lotterhos
- Department of Marine and Environmental Sciences, Northeastern University, 430 Nahant Road, Nahant, MA 01908, USA
| | - Ben Wielstra
- Institute of Biology Leiden, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands.,Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, The Netherlands
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