1
|
Cauret CMS, Jordan DC, Kukoly LM, Burton SR, Anele EU, Kwiecien JM, Gansauge MT, Senthillmohan S, Greenbaum E, Meyer M, Horb ME, Evans BJ. Functional dissection and assembly of a small, newly evolved, W chromosome-specific genomic region of the African clawed frog Xenopus laevis. PLoS Genet 2023; 19:e1010990. [PMID: 37792893 PMCID: PMC10578606 DOI: 10.1371/journal.pgen.1010990] [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: 03/07/2023] [Revised: 10/16/2023] [Accepted: 09/20/2023] [Indexed: 10/06/2023] Open
Abstract
Genetic triggers for sex determination are frequently co-inherited with other linked genes that may also influence one or more sex-specific phenotypes. To better understand how sex-limited regions evolve and function, we studied a small W chromosome-specific region of the frog Xenopus laevis that contains only three genes (dm-w, scan-w, ccdc69-w) and that drives female differentiation. Using gene editing, we found that the sex-determining function of this region requires dm-w but that scan-w and ccdc69-w are not essential for viability, female development, or fertility. Analysis of mesonephros+gonad transcriptomes during sexual differentiation illustrates masculinization of the dm-w knockout transcriptome, and identifies mostly non-overlapping sets of differentially expressed genes in separate knockout lines for each of these three W-specific gene compared to wildtype sisters. Capture sequencing of almost all Xenopus species and PCR surveys indicate that the female-determining function of dm-w is present in only a subset of species that carry this gene. These findings map out a dynamic evolutionary history of a newly evolved W chromosome-specific genomic region, whose components have distinctive functions that frequently degraded during Xenopus diversification, and evidence the evolutionary consequences of recombination suppression.
Collapse
Affiliation(s)
- Caroline M. S. Cauret
- Biology Department, McMaster University, Hamilton, Ontario, Canada
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Danielle C. Jordan
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
- The School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Sarah R. Burton
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
| | - Emmanuela U. Anele
- Biology Department, McMaster University, Hamilton, Ontario, Canada
- Department Zoology, Ahmadu Bello University, Zaria, Nigeria
| | - Jacek M. Kwiecien
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Marie-Theres Gansauge
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Eli Greenbaum
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Matthias Meyer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Marko E. Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
| | - Ben J. Evans
- Biology Department, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
2
|
Mrnjavac A, Khudiakova KA, Barton NH, Vicoso B. Slower-X: reduced efficiency of selection in the early stages of X chromosome evolution. Evol Lett 2023; 7:4-12. [PMID: 37065438 PMCID: PMC10091493 DOI: 10.1093/evlett/qrac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/08/2022] [Accepted: 12/17/2022] [Indexed: 02/04/2023] Open
Abstract
Abstract
Differentiated X chromosomes are expected to have higher rates of adaptive divergence than autosomes, if new beneficial mutations are recessive (the “faster-X effect”), largely because these mutations are immediately exposed to selection in males. The evolution of X chromosomes after they stop recombining in males, but before they become hemizygous, has not been well explored theoretically. We use the diffusion approximation to infer substitution rates of beneficial and deleterious mutations under such a scenario. Our results show that selection is less efficient on diploid X loci than on autosomal and hemizygous X loci under a wide range of parameters. This “slower-X” effect is stronger for genes affecting primarily (or only) male fitness, and for sexually antagonistic genes. These unusual dynamics suggest that some of the peculiar features of X chromosomes, such as the differential accumulation of genes with sex-specific functions, may start arising earlier than previously appreciated.
Collapse
Affiliation(s)
- Andrea Mrnjavac
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Ksenia A Khudiakova
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Nicholas H Barton
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Beatriz Vicoso
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| |
Collapse
|
3
|
Evans BJ, Mudd AB, Bredeson JV, Furman BLS, Wasonga DV, Lyons JB, Harland RM, Rokhsar DS. New insights into Xenopus sex chromosome genomics from the Marsabit clawed frog X. borealis. J Evol Biol 2022; 35:1777-1790. [PMID: 36054077 PMCID: PMC9722552 DOI: 10.1111/jeb.14078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/23/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022]
Abstract
In many groups, sex chromosomes change frequently but the drivers of their rapid evolution are varied and often poorly characterized. With an aim of further understanding sex chromosome turnover, we investigated the polymorphic sex chromosomes of the Marsabit clawed frog, Xenopus borealis, using genomic data and a new chromosome-scale genome assembly. We confirmed previous findings that 54.1 Mb of chromosome 8L is sex-linked in animals from east Kenya and a laboratory strain, but most (or all) of this region is not sex-linked in natural populations from west Kenya. Previous work suggests possible degeneration of the Z chromosomes in the east population because many sex-linked transcripts of this female heterogametic population have female-biased expression, and we therefore expected this chromosome to not be present in the west population. In contrast, our simulations support a model where most or all of the sex-linked portion of the Z chromosome from the east acquired autosomal segregation in the west, and where much genetic variation specific to the large sex-linked portion of the W chromosome from the east is not present in the west. These recent changes are consistent with the hot-potato model, wherein sex chromosome turnover is favoured by natural selection if it purges a (minimally) degenerate sex-specific sex chromosome, but counterintuitively suggest natural selection failed to purge a Z chromosome that has signs of more advanced and possibly more ancient regulatory degeneration. These findings highlight complex evolutionary dynamics of young, rapidly evolving Xenopus sex chromosomes and set the stage for mechanistic work aimed at pinpointing additional sex-determining genes in this group.
Collapse
Affiliation(s)
- Ben J Evans
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
| | - Austin B Mudd
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Jessen V Bredeson
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Benjamin L S Furman
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
- Canexia Health, Vancouver, British Columbia, Canada
| | | | - Jessica B Lyons
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Richard M Harland
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Dan S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Okinawa Institute of Science and Technology Graduate University, Onna, Japan
- Chan-Zuckerberg BioHub, San Francisco, California, USA
| |
Collapse
|
4
|
Nürnberger B, Baird SJE, Čížková D, Bryjová A, Mudd AB, Blaxter ML, Szymura JM. A dense linkage map for a large repetitive genome: discovery of the sex-determining region in hybridizing fire-bellied toads (Bombina bombina and Bombina variegata). G3 (BETHESDA, MD.) 2021; 11:6353606. [PMID: 34849761 PMCID: PMC8664441 DOI: 10.1093/g3journal/jkab286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/16/2021] [Indexed: 12/20/2022]
Abstract
Genomic analysis of hybrid zones offers unique insights into emerging reproductive isolation and the dynamics of introgression. Because hybrid genomes consist of blocks inherited from one or the other parental taxon, linkage information is essential. In most cases, the spectrum of local ancestry tracts can be efficiently uncovered from dense linkage maps. Here, we report the development of such a map for the hybridizing toads, Bombina bombina and Bombina variegata (Anura: Bombinatoridae). Faced with the challenge of a large (7–10 Gb), repetitive genome, we set out to identify a large number of Mendelian markers in the nonrepetitive portion of the genome that report B. bombina vs B. variegata ancestry with appropriately quantified statistical support. Bait sequences for targeted enrichment were selected from a draft genome assembly, after filtering highly repetitive sequences. We developed a novel approach to infer the most likely diplotype per sample and locus from the raw read mapping data, which is robust to over-merging and obviates arbitrary filtering thresholds. Validation of the resulting map with 4755 markers underscored the large-scale synteny between Bombina and Xenopus tropicalis. By assessing the sex of late-stage F2 tadpoles from histological sections, we identified the sex-determining region in the Bombina genome to 7 cM on LG5, which is homologous to X. tropicalis chromosome 5, and inferred male heterogamety. Interestingly, chromosome 5 has been repeatedly recruited as a sex chromosome in anurans with XY sex determination.
Collapse
Affiliation(s)
- Beate Nürnberger
- Research Facility Studenec, Institute of Vertebrate Biology, Czech Academy of Sciences, 603 65 Brno, Czech Republic
| | - Stuart J E Baird
- Research Facility Studenec, Institute of Vertebrate Biology, Czech Academy of Sciences, 603 65 Brno, Czech Republic
| | - Dagmar Čížková
- Research Facility Studenec, Institute of Vertebrate Biology, Czech Academy of Sciences, 603 65 Brno, Czech Republic
| | - Anna Bryjová
- Research Facility Studenec, Institute of Vertebrate Biology, Czech Academy of Sciences, 603 65 Brno, Czech Republic
| | - Austin B Mudd
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, 94720 CA, USA
| | - Mark L Blaxter
- Tree of Life Programme, Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Jacek M Szymura
- Department of Comparative Anatomy, Jagiellonian University, 30-387 Kraków, Poland
| |
Collapse
|
5
|
Okuno M, Mizushima S, Kuroiwa A, Itoh T. Analysis of Sex Chromosome Evolution in the Clade Palaeognathae from Phased Genome Assembly. Genome Biol Evol 2021; 13:6413640. [PMID: 34718546 PMCID: PMC8599748 DOI: 10.1093/gbe/evab242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2021] [Indexed: 12/30/2022] Open
Abstract
Birds in the clade Palaeognathae, excluding Tinamiformes, have morphologically conserved karyotypes and less differentiated ZW sex chromosomes compared with those of other birds. In particular, the sex chromosomes of the ostrich and emu have exceptionally large recombining pseudoautosomal regions (PARs), whereas non-PARs are classified into two strata according to the date of their origins: stratum 0 and stratum 1 (S1). However, the construction and analysis of the genome sequences in these regions in the clade Palaeognathae can be challenging because assembling the S1 region is difficult owing to low sequence diversity between gametologs (Z-linked and W-linked sequences). We addressed this issue by applying the Platanus-allee assembler and successfully constructed the haplotype-resolved (phased) assembly for female emu, cassowary, and ostrich using only sequence read data derived from the Illumina platform. Comparative genomic and phylogenetic analyses based on assembled Z-linked and W-linked sequences confirmed that the S1 region of emu and cassowary formed in their common ancestor. Moreover, the interspersed repetitive sequence landscapes in the S1 regions of female emu showed an expansion of younger repetitive elements in the W-linked S1 region, suggesting an interruption in homologous recombination in the S1 region. These results provide novel insights into the trajectory of sex chromosome evolution in the clade Palaeognathae and suggest that the Illumina-based phased assembly method is an effective approach for elucidating the evolutionary process underlying the transition from homomorphic to differentiated sex chromosomes.
Collapse
Affiliation(s)
- Miki Okuno
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.,Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan
| | - Shusei Mizushima
- Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Asato Kuroiwa
- Division of Reproductive and Developmental Biology, Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| |
Collapse
|
6
|
Roco ÁS, Ruiz-García A, Bullejos M. Interaction between sex-determining genes from two species: clues from Xenopus hybrids. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200104. [PMID: 34304589 PMCID: PMC8310712 DOI: 10.1098/rstb.2020.0104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2020] [Indexed: 12/13/2022] Open
Abstract
Hybrids provide an interesting model to study the evolution of sex-determining genes and sex chromosome systems as they offer the opportunity to see how independently evolving sex-determining pathways interact in vivo. In this context, the genus Xenopus represents a stimulating model, since species with non-homologous sex chromosomes and different sex-determining genes have been identified. In addition, the possibility of interspecies breeding is favoured in this group, which arose by alloploidization events, with species ploidy ranging from 2n = 2x = 20 in X. tropicalis (the only diploid representative of the genus) to 2n = 12x = 108 in X. ruwenzoriensis. To study how two sex-determining genes interact in vivo, X. laevis × X. tropicalis hybrids were produced. Gonadal differentiation in these hybrids revealed that the dm-w gene is dominant over X. tropicalis male-determining sex chromosomes (Y or Z), even though the Y chromosome is dominant in X. tropicalis (Y > W>Z). In the absence of the dm-w gene (the Z chromosome from X. laevis is present), the W chromosome from X. tropicalis is able to trigger ovarian development. Testicular differentiation will take place in the absence of W chromosomes from any of the parental species. The dominance/recessivity relationships between these sex-determining loci in the context of either parental genome remains unknown. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
Collapse
Affiliation(s)
- Álvaro S. Roco
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
| | - Adrián Ruiz-García
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
| | - Mónica Bullejos
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
| |
Collapse
|
7
|
Stöck M, Dedukh D, Reifová R, Lamatsch DK, Starostová Z, Janko K. Sex chromosomes in meiotic, hemiclonal, clonal and polyploid hybrid vertebrates: along the 'extended speciation continuum'. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200103. [PMID: 34304588 PMCID: PMC8310718 DOI: 10.1098/rstb.2020.0103] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2021] [Indexed: 12/15/2022] Open
Abstract
We review knowledge about the roles of sex chromosomes in vertebrate hybridization and speciation, exploring a gradient of divergences with increasing reproductive isolation (speciation continuum). Under early divergence, well-differentiated sex chromosomes in meiotic hybrids may cause Haldane-effects and introgress less easily than autosomes. Undifferentiated sex chromosomes are more susceptible to introgression and form multiple (or new) sex chromosome systems with hardly predictable dominance hierarchies. Under increased divergence, most vertebrates reach complete intrinsic reproductive isolation. Slightly earlier, some hybrids (linked in 'the extended speciation continuum') exhibit aberrant gametogenesis, leading towards female clonality. This facilitates the evolution of various allodiploid and allopolyploid clonal ('asexual') hybrid vertebrates, where 'asexuality' might be a form of intrinsic reproductive isolation. A comprehensive list of 'asexual' hybrid vertebrates shows that they all evolved from parents with divergences that were greater than at the intraspecific level (K2P-distances of greater than 5-22% based on mtDNA). These 'asexual' taxa inherited genetic sex determination by mostly undifferentiated sex chromosomes. Among the few known sex-determining systems in hybrid 'asexuals', female heterogamety (ZW) occurred about twice as often as male heterogamety (XY). We hypothesize that pre-/meiotic aberrations in all-female ZW-hybrids present Haldane-effects promoting their evolution. Understanding the preconditions to produce various clonal or meiotic allopolyploids appears crucial for insights into the evolution of sex, 'asexuality' and polyploidy. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
Collapse
Affiliation(s)
- Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries - IGB (Forschungsverbund Berlin), Müggelseedamm 301, 12587 Berlin, Germany
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Dmitrij Dedukh
- Institute of Animal Physiology and Genetics, Laboratory of Fish Genetics, The Czech Academy of Sciences, 277 21 Libechov, Czech Republic
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
| | - Dunja K. Lamatsch
- Research Department for Limnology, University of Innsbruck, Mondseestrasse 9, A-5310 Mondsee, Austria
| | - Zuzana Starostová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
| | - Karel Janko
- Institute of Animal Physiology and Genetics, Laboratory of Fish Genetics, The Czech Academy of Sciences, 277 21 Libechov, Czech Republic
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 701 03 Ostrava, Czech Republic
| |
Collapse
|
8
|
Kuhl H, Guiguen Y, Höhne C, Kreuz E, Du K, Klopp C, Lopez-Roques C, Yebra-Pimentel ES, Ciorpac M, Gessner J, Holostenco D, Kleiner W, Kohlmann K, Lamatsch DK, Prokopov D, Bestin A, Bonpunt E, Debeuf B, Haffray P, Morvezen R, Patrice P, Suciu R, Dirks R, Wuertz S, Kloas W, Schartl M, Stöck M. A 180 Myr-old female-specific genome region in sturgeon reveals the oldest known vertebrate sex determining system with undifferentiated sex chromosomes. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200089. [PMID: 34247507 PMCID: PMC8273502 DOI: 10.1098/rstb.2020.0089] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Several hypotheses explain the prevalence of undifferentiated sex chromosomes in poikilothermic vertebrates. Turnovers change the master sex determination gene, the sex chromosome or the sex determination system (e.g. XY to WZ). Jumping master genes stay main triggers but translocate to other chromosomes. Occasional recombination (e.g. in sex-reversed females) prevents sex chromosome degeneration. Recent research has uncovered conserved heteromorphic or even homomorphic sex chromosomes in several clades of non-avian and non-mammalian vertebrates. Sex determination in sturgeons (Acipenseridae) has been a long-standing basic biological question, linked to economical demands by the caviar-producing aquaculture. Here, we report the discovery of a sex-specific sequence from sterlet (Acipenser ruthenus). Using chromosome-scale assemblies and pool-sequencing, we first identified an approximately 16 kb female-specific region. We developed a PCR-genotyping test, yielding female-specific products in six species, spanning the entire phylogeny with the most divergent extant lineages (A. sturio, A. oxyrinchus versus A. ruthenus, Huso huso), stemming from an ancient tetraploidization. Similar results were obtained in two octoploid species (A. gueldenstaedtii, A. baerii). Conservation of a female-specific sequence for a long period, representing 180 Myr of sturgeon evolution, and across at least one polyploidization event, raises many interesting biological questions. We discuss a conserved undifferentiated sex chromosome system with a ZZ/ZW-mode of sex determination and potential alternatives. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)’.
Collapse
Affiliation(s)
- Heiner Kuhl
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | | | - Christin Höhne
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Eva Kreuz
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Kang Du
- Developmental Biochemistry, Biocenter, University of Würzburg, 97074 Würzburg, Germany.,The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Christophe Klopp
- SIGENAE, Plate-forme Bio-informatique Genotoul, Mathématiques et Informatique Appliquées de Toulouse, INRAe, 31326 Castanet-Tolosan, France
| | | | | | - Mitica Ciorpac
- Danube Delta National Institute for Research and Development, Tulcea 820112, Romania.,Genetic Improvement Laboratory, Research Station for Cattle Breeding Dancu - Iasi (SCDCB Dancu), Academy of Agricultural and Forestry Sciences 'Gheorghe Ionescu-Sisesti', Iasi-Ungheni Street, No. 9, Holboca, Iași county 707252, Romania
| | - Jörn Gessner
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Daniela Holostenco
- Danube Delta National Institute for Research and Development, Tulcea 820112, Romania
| | - Wibke Kleiner
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Klaus Kohlmann
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Dunja K Lamatsch
- Research Department for Limnology, University of Innsbruck, A-5310 Mondsee, Austria
| | - Dmitry Prokopov
- Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Anastasia Bestin
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042 Rennes cedex, France
| | | | - Bastien Debeuf
- SCEA Sturgeon, 29 rue du Carillon, 17240 Saint Fort sur Gironde, France
| | - Pierrick Haffray
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042 Rennes cedex, France
| | - Romain Morvezen
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042 Rennes cedex, France
| | - Pierre Patrice
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042 Rennes cedex, France
| | - Radu Suciu
- Danube Delta National Institute for Research and Development, Tulcea 820112, Romania
| | - Ron Dirks
- Future Genomics Technologies B.V., Sylviusweg 74, 2333 BD, Leiden, The Netherlands
| | - Sven Wuertz
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Werner Kloas
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| | - Manfred Schartl
- Developmental Biochemistry, Biocenter, University of Würzburg, 97074 Würzburg, Germany.,The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Matthias Stöck
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 and 310, 12587 Berlin, Germany
| |
Collapse
|
9
|
Song XY, Furman BLS, Premachandra T, Knytl M, Cauret CMS, Wasonga DV, Measey J, Dworkin I, Evans BJ. Sex chromosome degeneration, turnover, and sex-biased expression of sex-linked transcripts in African clawed frogs ( Xenopus). Philos Trans R Soc Lond B Biol Sci 2021; 376:20200095. [PMID: 34247503 DOI: 10.1098/rstb.2020.0095] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The tempo of sex chromosome evolution-how quickly, in what order, why and how their particular characteristics emerge during evolution-remains poorly understood. To understand this further, we studied three closely related species of African clawed frog (genus Xenopus), that each has independently evolved sex chromosomes. We identified population polymorphism in the extent of sex chromosome differentiation in wild-caught Xenopus borealis that corresponds to a large, previously identified region of recombination suppression. This large sex-linked region of X. borealis has an extreme concentration of genes that encode transcripts with sex-biased expression, and we recovered similar findings in the smaller sex-linked regions of Xenopus laevis and Xenopus tropicalis. In two of these species, strong skews in expression (mostly female-biased in X. borealis, mostly male-biased in X. tropicalis) are consistent with expectations associated with recombination suppression, and in X. borealis, we hypothesize that a degenerate ancestral Y-chromosome transitioned into its contemporary Z-chromosome. These findings indicate that Xenopus species are tolerant of differences between the sexes in dosage of the products of multiple genes, and offer insights into how evolutionary transformations of ancestral sex chromosomes carry forward to affect the function of new sex chromosomes. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)'.
Collapse
Affiliation(s)
- Xue-Ying Song
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Benjamin L S Furman
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.,Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
| | - Tharindu Premachandra
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Martin Knytl
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.,Department of Cell Biology, Charles University, 7 Vinicna Street, Prague 12843, Czech Republic
| | - Caroline M S Cauret
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | | | - John Measey
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa
| | - Ian Dworkin
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Ben J Evans
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| |
Collapse
|
10
|
Ruiz-García A, Roco ÁS, Bullejos M. Sex Differentiation in Amphibians: Effect of Temperature and Its Influence on Sex Reversal. Sex Dev 2021; 15:157-167. [PMID: 34000727 DOI: 10.1159/000515220] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/20/2020] [Indexed: 11/19/2022] Open
Abstract
The role of environmental factors in sexual differentiation in amphibians is not new. The effect of hormones or hormone-like compounds is widely demonstrated. However, the effect of temperature has traditionally been regarded as something anecdotal that occurs in extreme situations and not as a factor to be considered. The data currently available reveal a different situation. Sexual differentiation in some amphibian species can be altered even by small changes in temperature. On the other hand, although not proven, it is possible that temperature is related to the appearance of sex-reversed individuals in natural populations under conditions unrelated to environmental contaminants. According to this, temperature, through sex reversal (phenotypic sex opposed to genetic sex), could play an important role in the turnover of sex-determining genes and in the maintenance of homomorphic sex chromosomes in this group. Accordingly, and given the expected increase in global temperatures, growth and sexual differentiation in amphibians could easily be affected, altering the sex ratio in natural populations and posing major conservation challenges for a group in worldwide decline. It is therefore particularly urgent to understand the mechanism by which temperature affects sexual differentiation in amphibians.
Collapse
Affiliation(s)
- Adrián Ruiz-García
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
| | - Álvaro S Roco
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
| | - Mónica Bullejos
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
| |
Collapse
|
11
|
Roco ÁS, Liehr T, Ruiz-García A, Guzmán K, Bullejos M. Comparative Distribution of Repetitive Sequences in the Karyotypes of Xenopus tropicalis and Xenopus laevis (Anura, Pipidae). Genes (Basel) 2021; 12:617. [PMID: 33919402 PMCID: PMC8143290 DOI: 10.3390/genes12050617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 11/29/2022] Open
Abstract
Xenopus laevis and its diploid relative, Xenopus tropicalis, are the most used amphibian models. Their genomes have been sequenced, and they are emerging as model organisms for research into disease mechanisms. Despite the growing knowledge on their genomes based on data obtained from massive genome sequencing, basic research on repetitive sequences in these species is lacking. This study conducted a comparative analysis of repetitive sequences in X. laevis and X. tropicalis. Genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) with Cot DNA of both species revealed a conserved enrichment of repetitive sequences at the ends of the chromosomes in these Xenopus species. The repeated sequences located on the short arm of chromosome 3 from X. tropicalis were not related to the sequences on the short arm of chromosomes 3L and 3S from X. laevis, although these chromosomes were homoeologous, indicating that these regions evolved independently in these species. Furthermore, all the other repetitive sequences in X. tropicalis and X. laevis may be species-specific, as they were not revealed in cross-species hybridizations. Painting experiments in X. laevis with chromosome 7 from X. tropicalis revealed shared sequences with the short arm of chromosome 3L. These regions could be related by the presence of the nucleolus organizer region (NOR) in both chromosomes, although the region revealed by chromosome painting in the short arm of chromosome 3L in X. laevis did not correspond to 18S + 28S rDNA sequences, as they did not colocalize. The identification of these repeated sequences is of interest as they provide an explanation to some problems already described in the genome assemblies of these species. Furthermore, the distribution of repetitive DNA in the genomes of X. laevis and X. tropicalis might be a valuable marker to assist us in understanding the genome evolution in a group characterized by numerous polyploidization events coupled with hybridizations.
Collapse
Affiliation(s)
- Álvaro S. Roco
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain; (Á.S.R.); (A.R.-G.); (K.G.)
| | - Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Am Klinikum 1, D-07747 Jena, Germany;
| | - Adrián Ruiz-García
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain; (Á.S.R.); (A.R.-G.); (K.G.)
| | - Kateryna Guzmán
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain; (Á.S.R.); (A.R.-G.); (K.G.)
| | - Mónica Bullejos
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain; (Á.S.R.); (A.R.-G.); (K.G.)
| |
Collapse
|
12
|
Roco ÁS, Ruiz-García A, Bullejos M. Testis Development and Differentiation in Amphibians. Genes (Basel) 2021; 12:578. [PMID: 33923451 PMCID: PMC8072878 DOI: 10.3390/genes12040578] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/08/2021] [Accepted: 04/14/2021] [Indexed: 11/17/2022] Open
Abstract
Sex is determined genetically in amphibians; however, little is known about the sex chromosomes, testis-determining genes, and the genes involved in testis differentiation in this class. Certain inherent characteristics of the species of this group, like the homomorphic sex chromosomes, the high diversity of the sex-determining mechanisms, or the existence of polyploids, may hinder the design of experiments when studying how the gonads can differentiate. Even so, other features, like their external development or the possibility of inducing sex reversal by external treatments, can be helpful. This review summarizes the current knowledge on amphibian sex determination, gonadal development, and testis differentiation. The analysis of this information, compared with the information available for other vertebrate groups, allows us to identify the evolutionarily conserved and divergent pathways involved in testis differentiation. Overall, the data confirm the previous observations in other vertebrates-the morphology of the adult testis is similar across different groups; however, the male-determining signal and the genetic networks involved in testis differentiation are not evolutionarily conserved.
Collapse
Affiliation(s)
| | | | - Mónica Bullejos
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Campus Las Lagunillas S/N, Universidad de Jaén, 23071 Jaén, Spain; (Á.S.R.); (A.R.-G.)
| |
Collapse
|
13
|
Ma WJ, Veltsos P. The Diversity and Evolution of Sex Chromosomes in Frogs. Genes (Basel) 2021; 12:483. [PMID: 33810524 PMCID: PMC8067296 DOI: 10.3390/genes12040483] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 11/30/2022] Open
Abstract
Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.
Collapse
Affiliation(s)
- Wen-Juan Ma
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Paris Veltsos
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA;
| |
Collapse
|
14
|
Lamichhaney S, Catullo R, Keogh JS, Clulow S, Edwards SV, Ezaz T. A bird-like genome from a frog: Mechanisms of genome size reduction in the ornate burrowing frog, Platyplectrum ornatum. Proc Natl Acad Sci U S A 2021; 118:e2011649118. [PMID: 33836564 PMCID: PMC7980411 DOI: 10.1073/pnas.2011649118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The diversity of genome sizes across the tree of life is of key interest in evolutionary biology. Various correlates of variation in genome size, such as accumulation of transposable elements (TEs) or rate of DNA gain and loss, are well known, but the underlying molecular mechanisms driving or constraining genome size are poorly understood. Here, we study one of the smallest genomes among frogs characterized thus far, that of the ornate burrowing frog (Platyplectrum ornatum) from Australia, and compare it to other published frog and vertebrate genomes to examine the forces driving reduction in genome size. At ∼1.06 gigabases (Gb), the P. ornatum genome is like that of birds, revealing four major mechanisms underlying TE dynamics: reduced abundance of all major classes of TEs; increased net deletion bias in TEs; drastic reduction in intron lengths; and expansion via gene duplication of the repertoire of TE-suppressing Piwi genes, accompanied by increased expression of Piwi-interacting RNA (piRNA)-based TE-silencing pathway genes in germline cells. Transcriptomes from multiple tissues in both sexes corroborate these results and provide insight into sex-differentiation pathways in Platyplectrum Genome skimming of two closely related frog species (Lechriodus fletcheri and Limnodynastes fletcheri) confirms a reduction in TEs as a major driver of genome reduction in Platyplectrum and supports a macroevolutionary scenario of small genome size in frogs driven by convergence in life history, especially rapid tadpole development and tadpole diet. The P. ornatum genome offers a model for future comparative studies on mechanisms of genome size reduction in amphibians and vertebrates generally.
Collapse
Affiliation(s)
- Sangeet Lamichhaney
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138
| | - Renee Catullo
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Acton, ACT, Australia 2601
- Australian National Insect Collection and Future Science Platform Environomics, Commonwealth Scientific and Industrial Research Organization, Acton, ACT, Australia 2601
| | - J Scott Keogh
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Acton, ACT, Australia 2601
| | - Simon Clulow
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia 2109
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138;
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138
| | - Tariq Ezaz
- Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia 2617
| |
Collapse
|
15
|
Furman BLS, Metzger DCH, Darolti I, Wright AE, Sandkam BA, Almeida P, Shu JJ, Mank JE. Sex Chromosome Evolution: So Many Exceptions to the Rules. Genome Biol Evol 2020; 12:750-763. [PMID: 32315410 PMCID: PMC7268786 DOI: 10.1093/gbe/evaa081] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2020] [Indexed: 01/10/2023] Open
Abstract
Genomic analysis of many nonmodel species has uncovered an incredible diversity of sex chromosome systems, making it possible to empirically test the rich body of evolutionary theory that describes each stage of sex chromosome evolution. Classic theory predicts that sex chromosomes originate from a pair of homologous autosomes and recombination between them is suppressed via inversions to resolve sexual conflict. The resulting degradation of the Y chromosome gene content creates the need for dosage compensation in the heterogametic sex. Sex chromosome theory also implies a linear process, starting from sex chromosome origin and progressing to heteromorphism. Despite many convergent genomic patterns exhibited by independently evolved sex chromosome systems, and many case studies supporting these theoretical predictions, emerging data provide numerous interesting exceptions to these long-standing theories, and suggest that the remarkable diversity of sex chromosomes is matched by a similar diversity in their evolution. For example, it is clear that sex chromosome pairs are not always derived from homologous autosomes. In addition, both the cause and the mechanism of recombination suppression between sex chromosome pairs remain unclear, and it may be that the spread of recombination suppression is a more gradual process than previously thought. It is also clear that dosage compensation can be achieved in many ways, and displays a range of efficacy in different systems. Finally, the remarkable turnover of sex chromosomes in many systems, as well as variation in the rate of sex chromosome divergence, suggest that assumptions about the inevitable linearity of sex chromosome evolution are not always empirically supported, and the drivers of the birth-death cycle of sex chromosome evolution remain to be elucidated. Here, we concentrate on how the diversity in sex chromosomes across taxa highlights an equal diversity in each stage of sex chromosome evolution.
Collapse
Affiliation(s)
- Benjamin L S Furman
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David C H Metzger
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Iulia Darolti
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alison E Wright
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
| | - Benjamin A Sandkam
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pedro Almeida
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| | - Jacelyn J Shu
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Judith E Mank
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| |
Collapse
|
16
|
Abstract
Sex differences in overall recombination rates are well known, but little theoretical or empirical attention has been given to how and why sexes differ in their recombination landscapes: the patterns of recombination along chromosomes. In the first scientific review of this phenomenon, we find that recombination is biased toward telomeres in males and more uniformly distributed in females in most vertebrates and many other eukaryotes. Notable exceptions to this pattern exist, however. Fine-scale recombination patterns also frequently differ between males and females. The molecular mechanisms responsible for sex differences remain unclear, but chromatin landscapes play a role. Why these sex differences evolve also is unclear. Hypotheses suggest that they may result from sexually antagonistic selection acting on coding genes and their regulatory elements, meiotic drive in females, selection during the haploid phase of the life cycle, selection against aneuploidy, or mechanistic constraints. No single hypothesis, however, can adequately explain the evolution of sex differences in all cases. Sex-specific recombination landscapes have important consequences for population differentiation and sex chromosome evolution.
Collapse
Affiliation(s)
- Jason M. Sardell
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
| | - Mark Kirkpatrick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
| |
Collapse
|
17
|
Cauret CMS, Gansauge MT, Tupper AS, Furman BLS, Knytl M, Song XY, Greenbaum E, Meyer M, Evans BJ. Developmental Systems Drift and the Drivers of Sex Chromosome Evolution. Mol Biol Evol 2019; 37:799-810. [DOI: 10.1093/molbev/msz268] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AbstractPhenotypic invariance—the outcome of purifying selection—is a hallmark of biological importance. However, invariant phenotypes might be controlled by diverged genetic systems in different species. Here, we explore how an important and invariant phenotype—the development of sexually differentiated individuals—is controlled in over two dozen species in the frog family Pipidae. We uncovered evidence in different species for 1) an ancestral W chromosome that is not found in many females and is found in some males, 2) independent losses and 3) autosomal segregation of this W chromosome, 4) changes in male versus female heterogamy, and 5) substantial variation among species in recombination suppression on sex chromosomes. We further provide evidence of, and evolutionary context for, the origins of at least seven distinct systems for regulating sex determination among three closely related genera. These systems are distinct in their genomic locations, evolutionary origins, and/or male versus female heterogamy. Our findings demonstrate that the developmental control of sexual differentiation changed via loss, sidelining, and empowerment of a mechanistically influential gene, and offer insights into novel factors that impinge on the diverse evolutionary fates of sex chromosomes.
Collapse
Affiliation(s)
| | - Marie-Theres Gansauge
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Andrew S Tupper
- Origins Institute and Department of Biochemistry and Biomedical Science, McMaster University, Hamilton, Canada
| | - Benjamin L S Furman
- Biology Department, McMaster University, Hamilton, Canada
- Department of Zoology, Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - Martin Knytl
- Biology Department, McMaster University, Hamilton, Canada
- Department of Cell Biology, Charles University, Prague 2, Czech Republic
| | - Xue-Ying Song
- Biology Department, McMaster University, Hamilton, Canada
| | - Eli Greenbaum
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX
| | - Matthias Meyer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Ben J Evans
- Biology Department, McMaster University, Hamilton, Canada
| |
Collapse
|