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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.
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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
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2
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Panthum T, Jaisamut K, Singchat W, Ahmad SF, Kongkaew L, Wongloet W, Dokkaew S, Kraichak E, Muangmai N, Duengkae P, Srikulnath K. Something Fishy about Siamese Fighting Fish ( Betta splendens) Sex: Polygenic Sex Determination or a Newly Emerged Sex-Determining Region? Cells 2022; 11:1764. [PMID: 35681459 PMCID: PMC9179492 DOI: 10.3390/cells11111764] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 12/04/2022] Open
Abstract
Fishes provide a unique and intriguing model system for studying the genomic origin and evolutionary mechanisms underlying sex determination and high sex-chromosome turnover. In this study, the mode of sex determination was investigated in Siamese fighting fish, a species of commercial importance. Genome-wide SNP analyses were performed on 75 individuals (40 males and 35 females) across commercial populations to determine candidate sex-specific/sex-linked loci. In total, 73 male-specific loci were identified and mapped to a 5.6 kb region on chromosome 9, suggesting a putative male-determining region (pMDR) containing localized dmrt1 and znrf3 functional sex developmental genes. Repeat annotations of the pMDR revealed an abundance of transposable elements, particularly Ty3/Gypsy and novel repeats. Remarkably, two out of the 73 male-specific loci were located on chromosomes 7 and 19, implying the existence of polygenic sex determination. Besides male-specific loci, five female-specific loci on chromosome 9 were also observed in certain populations, indicating the possibility of a female-determining region and the polygenic nature of sex determination. An alternative explanation is that male-specific loci derived from other chromosomes or female-specific loci in Siamese fighting fish recently emerged as new sex-determining loci during domestication and repeated hybridization.
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Affiliation(s)
- Thitipong Panthum
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Interdisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Kitipong Jaisamut
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Worapong Singchat
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Syed Farhan Ahmad
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
| | - Lalida Kongkaew
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Wongsathit Wongloet
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Sahabhop Dokkaew
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand;
| | - Ekaphan Kraichak
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Department of Botany, Kasetsart University, Bangkok 10900, Thailand
| | - Narongrit Muangmai
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand
| | - Prateep Duengkae
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Kornsorn Srikulnath
- Animal Genomics and Bioresource Research Unit (AGB Research Unit), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.J.); (W.S.); (S.F.A.); (L.K.); (W.W.); (E.K.); (N.M.); (P.D.)
- Interdisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Kasetsart University, (CASTNAR, NRU-KU, Thailand), Bangkok 10900, Thailand
- Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok 10900, Thailand
- Amphibian Research Center, Hiroshima University, Kagamiyama, Higashihiroshima 739-8527, Japan
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3
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Saunders PA, Perez J, Ronce O, Veyrunes F. Multiple sex chromosome drivers in a mammal with three sex chromosomes. Curr Biol 2022; 32:2001-2010.e3. [PMID: 35381184 DOI: 10.1016/j.cub.2022.03.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/06/2022] [Accepted: 03/10/2022] [Indexed: 12/22/2022]
Abstract
Eukaryotes with separate males and females display a great diversity in the way they determine sex, but it is still unclear what evolutionary forces cause transitions between sex-determining systems. Rather that the lack of hypotheses, the problem is the scarcity of adequate biological systems to test them. Here, we take advantage of the recent evolution of a feminizing X chromosome (called X∗) in the African pygmy mouse Mus minutoides to investigate one of the evolutionary forces hypothesized to cause such transitions, namely sex chromosome drive (i.e., biased transmission of sex chromosomes to the next generation). Through extensive molecular sexing of pups at weaning, we reveal the existence of a remarkable male sex chromosome drive system in this species, whereby direction and strength of drive are conditional upon the genotype of males' partners: males transmit their Y at a rate close to 80% when mating with XX or XX∗ females and only 36% when mating with X∗Y females. Using mathematical modeling, we explore the joint evolution of these unusual sex-determining and drive systems, revealing that different sequences of events could have led to the evolution of this bizarre system and that the "conditional" nature of sex chromosome drive plays a crucial role in the short- and long-term maintenance of the three sex chromosomes.
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Affiliation(s)
- Paul A Saunders
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554 (CNRS, Université de Montpellier, IRD, EPHE), 34090 Montpellier, France.
| | - Julie Perez
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554 (CNRS, Université de Montpellier, IRD, EPHE), 34090 Montpellier, France
| | - Ophélie Ronce
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554 (CNRS, Université de Montpellier, IRD, EPHE), 34090 Montpellier, France
| | - Frédéric Veyrunes
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554 (CNRS, Université de Montpellier, IRD, EPHE), 34090 Montpellier, France
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4
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Feller AF, Ogi V, Seehausen O, Meier JI. Identification of a novel sex determining chromosome in cichlid fishes that acts as XY or ZW in different lineages. HYDROBIOLOGIA 2021; 848:3727-3745. [PMID: 34720170 PMCID: PMC8550731 DOI: 10.1007/s10750-021-04560-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 02/02/2021] [Accepted: 02/23/2021] [Indexed: 05/02/2023]
Abstract
UNLABELLED Sex determination systems are highly conserved among most vertebrates with genetic sex determination, but can be variable and evolve rapidly in some. Here, we study sex determination in a clade with exceptionally high sex chromosome turnover rates. We identify the sex determining chromosomes in three interspecific crosses of haplochromine cichlid fishes from Lakes Victoria and Malawi. We find evidence for different sex determiners in each cross. In the Malawi cross and one Victoria cross the same chromosome is sex-linked but while females are the heterogametic sex in the Malawi species, males are the heterogametic sex in the Victoria species. This chromosome has not previously been reported to be sex determining in cichlids, increasing the number of different chromosomes shown to be sex determining in cichlids to 12. All Lake Victoria species of our crosses are less than 15,000 years divergent, and we identified different sex determiners among them. Our study provides further evidence for the diversity and evolutionary flexibility of sex determination in cichlids, factors which might contribute to their rapid adaptive radiations. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10750-021-04560-7.
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Affiliation(s)
- Anna F. Feller
- Division of Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry (CEEB), Eawag Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, 6047 Kastanienbaum, Switzerland
| | - Vera Ogi
- Division of Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry (CEEB), Eawag Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, 6047 Kastanienbaum, Switzerland
| | - Ole Seehausen
- Division of Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry (CEEB), Eawag Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, 6047 Kastanienbaum, Switzerland
| | - Joana I. Meier
- Division of Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry (CEEB), Eawag Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, 6047 Kastanienbaum, Switzerland
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
- St John’s College, University of Cambridge, St John’s Street, Cambridge, CB2 1TP UK
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5
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Furman BLS, Cauret CMS, Knytl M, Song XY, Premachandra T, Ofori-Boateng C, Jordan DC, Horb ME, Evans BJ. A frog with three sex chromosomes that co-mingle together in nature: Xenopus tropicalis has a degenerate W and a Y that evolved from a Z chromosome. PLoS Genet 2020; 16:e1009121. [PMID: 33166278 PMCID: PMC7652241 DOI: 10.1371/journal.pgen.1009121] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/16/2020] [Indexed: 11/18/2022] Open
Abstract
In many species, sexual differentiation is a vital prelude to reproduction, and disruption of this process can have severe fitness effects, including sterility. It is thus interesting that genetic systems governing sexual differentiation vary among-and even within-species. To understand these systems more, we investigated a rare example of a frog with three sex chromosomes: the Western clawed frog, Xenopus tropicalis. We demonstrate that natural populations from the western and eastern edges of Ghana have a young Y chromosome, and that a male-determining factor on this Y chromosome is in a very similar genomic location as a previously known female-determining factor on the W chromosome. Nucleotide polymorphism of expressed transcripts suggests genetic degeneration on the W chromosome, emergence of a new Y chromosome from an ancestral Z chromosome, and natural co-mingling of the W, Z, and Y chromosomes in the same population. Compared to the rest of the genome, a small sex-associated portion of the sex chromosomes has a 50-fold enrichment of transcripts with male-biased expression during early gonadal differentiation. Additionally, X. tropicalis has sex-differences in the rates and genomic locations of recombination events during gametogenesis that are similar to at least two other Xenopus species, which suggests that sex differences in recombination are genus-wide. These findings are consistent with theoretical expectations associated with recombination suppression on sex chromosomes, demonstrate that several characteristics of old and established sex chromosomes (e.g., nucleotide divergence, sex biased expression) can arise well before sex chromosomes become cytogenetically distinguished, and show how these characteristics can have lingering consequences that are carried forward through sex chromosome turnovers.
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Affiliation(s)
- Benjamin L. S. Furman
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- Department of Zoology, University of British Columbia, 6270 University Blvd Vancouver, British Columbia, V6T 1Z4 Canada
| | - Caroline M. S. Cauret
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Martin Knytl
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- Department of Cell Biology, Charles University, 7 Vinicna Street, Prague, 12843, Czech Republic
| | - Xue-Ying Song
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Tharindu Premachandra
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | | | - Danielle C. Jordan
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, 7 MBL St, Woods Hole, MA 02543 USA
| | - Marko E. Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, 7 MBL St, Woods Hole, MA 02543 USA
| | - Ben J. Evans
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
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6
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Runemark A, Eroukhmanoff F, Nava-Bolaños A, Hermansen JS, Meier JI. Hybridization, sex-specific genomic architecture and local adaptation. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0419. [PMID: 30150218 DOI: 10.1098/rstb.2017.0419] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2018] [Indexed: 12/19/2022] Open
Abstract
While gene flow can reduce the potential for local adaptation, hybridization may conversely provide genetic variation that increases the potential for local adaptation. Hybridization may also affect adaptation through altering sexual dimorphism and sexual conflict, but this remains largely unstudied. Here, we discuss how hybridization may affect sexual dimorphism and conflict due to differential effects of hybridization on males and females, and then how this, in turn, may affect local adaptation. First, in species with heterochromatic sexes, the lower viability of the heterogametic sex in hybrids could shift the balance in sexual conflict. Second, sex-specific inheritance of the mitochondrial genome in hybrids may lead to cytonuclear mismatches, for example, in the form of 'mother's curse', with potential consequences for sex ratio and sex-specific expression. Third, sex-biased introgression and recombination may lead to sex-specific consequences of hybridization. Fourth, transgressive segregation of sexually antagonistic alleles could increase sexual dimorphism in hybrid populations. Sexual dimorphism can reduce sexual conflict and enhance intersexual niche partitioning, increasing the fitness of hybrids. Adaptive introgression of alleles reducing sexual conflict or enhancing intersexual niche partitioning may facilitate local adaptation, and could favour the colonization of novel habitats. We review these consequences of hybridization on sex differences and local adaptation, and discuss how their prevalence and importance could be tested empirically.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Anna Runemark
- Department of Biology, Lund University, 22362 Lund, Sweden
| | - Fabrice Eroukhmanoff
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway
| | - Angela Nava-Bolaños
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. Postal 70-275, Ciudad Universitaria, 04510 Ciudad de México, México
| | - Jo S Hermansen
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway
| | - Joana I Meier
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland.,Department of Fish Ecology and Evolution, EAWAG, 6047 Kastanienbaum, Switzerland
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7
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Perry C, Scanlan J, Robin C. Mining insect genomes for functionally affiliated genes. CURRENT OPINION IN INSECT SCIENCE 2019; 31:114-122. [PMID: 31109664 DOI: 10.1016/j.cois.2018.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Several hundred insect genome assemblies are already publicly available, and this total grows on a weekly basis. A major challenge now confronting insect science is how best to use genomic data to improve our understanding of insect biology. We consider a framework for genome analysis based on functional affiliation, that is, groups of genes involved in the same biological process or pathway, and explore how such an approach furthers our understanding of several aspects of insect phenotype. We anticipate that this approach will prove useful for future research across the breadth of insect studies, whatever organism or trait it involves.
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Affiliation(s)
- Caitlyn Perry
- The University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia.
| | - Jack Scanlan
- The University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - Charles Robin
- The University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
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8
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Martin H, Carpentier F, Gallina S, Godé C, Schmitt E, Muyle A, Marais GAB, Touzet P. Evolution of Young Sex Chromosomes in Two Dioecious Sister Plant Species with Distinct Sex Determination Systems. Genome Biol Evol 2019; 11:350-361. [PMID: 30649306 PMCID: PMC6364797 DOI: 10.1093/gbe/evz001] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2019] [Indexed: 12/14/2022] Open
Abstract
In the last decade, progress has been made in methods to identify the sex determination system in plants. This gives the opportunity to study sex chromosomes that arose independently at different phylogenetic scales, and thus allows the discovery and the understanding of early stages of sex chromosome evolution. In the genus Silene, sex chromosomes have evolved independently in at least two clades from a nondioecious ancestor, the Melandrium and Otites sections. In the latter, sex chromosomes could be younger than in the section Melandrium, based on phylogenetic studies and as no heteromorphic sex chromosomes have been detected. This section might also exhibit lability in sex determination, because male heterogamy and female heterogamy have been suggested to occur. In this study, we investigated the sex determination system of two dioecious species in the section Otites (Silene otites and its close relative Silene pseudotites). Applying the new probabilistic method SEX-DETector on RNA-seq data from cross-controlled progenies, we inferred their most likely sex determination system and a list of putative autosomal and sex-linked contigs. We showed that the two phylogenetically close species differed in their sex determination system (XY versus ZW) with sex chromosomes that derived from two different pairs of autosomes. We built a genetic map of the sex chromosomes and showed that both pairs exhibited a large region with lack of recombination. However, the sex-limited chromosomes exhibited no strong degeneration. Finally, using the “ancestral” autosomal expression of sex-linked orthologs of nondioecious S. nutans, we found a slight signature of dosage compensation in the heterogametic females of S. otites.
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Affiliation(s)
- Hélène Martin
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, France.,Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Canada
| | - Fantin Carpentier
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, France.,Ecologie Systématique Evolution, Université Paris Sud, AgroParisTech, CNRS, Université Paris-Saclay, Orsay, France
| | | | - Cécile Godé
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, France
| | - Eric Schmitt
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, France
| | - Aline Muyle
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France.,Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine
| | - Gabriel A B Marais
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
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9
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Saunders PA, Neuenschwander S, Perrin N. Sex chromosome turnovers and genetic drift: a simulation study. J Evol Biol 2018; 31:1413-1419. [PMID: 29923246 DOI: 10.1111/jeb.13336] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/23/2018] [Accepted: 06/17/2018] [Indexed: 01/18/2023]
Abstract
The recent advances of new genomic technologies have enabled the identification and characterization of sex chromosomes in an increasing number of nonmodel species, revealing that many plants and animals undergo frequent sex chromosome turnovers. What evolutionary forces drive these turnovers remains poorly understood, but it was recently proposed that drift might play a more important role than generally assumed. We analysed the dynamics of different types of turnovers using individual-based simulations and show that when mediated by genetic drift, turnovers are usually easier to achieve than substitutions at neutral markers, but that their dynamics and relative likelihoods vary with the type of the resident and emergent sex chromosome system (XY and/or ZW) and the dominance relationships among the sex-determining factors. Focusing on turnovers driven by epistatically dominant mutations, we find that drift-mediated turnovers that preserve the heterogamety pattern are 2-4× more likely than those along which the heterogametic sex changes. This ratio nevertheless decreases along with effective population size and can even reverse in case of extreme polygyny. This can be attributed to a 'drift-induced' selective force, known to influence transitions between male and female heterogamety, but which according to our study does not affect turnovers that preserve the heterogametic sex.
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Affiliation(s)
- Paul A Saunders
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland
| | - Samuel Neuenschwander
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland.,Vital-IT, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicolas Perrin
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland
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10
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Ponnikas S, Sigeman H, Abbott JK, Hansson B. Why Do Sex Chromosomes Stop Recombining? Trends Genet 2018; 34:492-503. [DOI: 10.1016/j.tig.2018.04.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 03/22/2018] [Accepted: 04/02/2018] [Indexed: 01/05/2023]
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Charlesworth D. The Guppy Sex Chromosome System and the Sexually Antagonistic Polymorphism Hypothesis for Y Chromosome Recombination Suppression. Genes (Basel) 2018; 9:genes9050264. [PMID: 29783761 PMCID: PMC5977204 DOI: 10.3390/genes9050264] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/11/2018] [Accepted: 05/16/2018] [Indexed: 02/06/2023] Open
Abstract
Sex chromosomes regularly evolve suppressed recombination, distinguishing them from other chromosomes, and the reason for this has been debated for many years. It is now clear that non-recombining sex-linked regions have arisen in different ways in different organisms. A major hypothesis is that a sex-determining gene arises on a chromosome and that sexually antagonistic (SA) selection (sometimes called intra-locus sexual conflict) acting at a linked gene has led to the evolution of recombination suppression in the region, to reduce the frequency of low fitness recombinant genotypes produced. The sex chromosome system of the guppy (Poecilia reticulata) is often cited as supporting this hypothesis because SA selection has been demonstrated to act on male coloration in natural populations of this fish, and probably contributes to maintaining polymorphisms for the genetic factors involved. I review classical genetic and new molecular genetic results from the guppy, and other fish, including approaches for identifying the genome regions carrying sex-determining loci, and suggest that the guppy may exemplify a recently proposed route to sex chromosome evolution.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK.
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12
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Abbott JK, Nordén AK, Hansson B. Sex chromosome evolution: historical insights and future perspectives. Proc Biol Sci 2018; 284:rspb.2016.2806. [PMID: 28469017 PMCID: PMC5443938 DOI: 10.1098/rspb.2016.2806] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/04/2017] [Indexed: 12/26/2022] Open
Abstract
Many separate-sexed organisms have sex chromosomes controlling sex determination. Sex chromosomes often have reduced recombination, specialized (frequently sex-specific) gene content, dosage compensation and heteromorphic size. Research on sex determination and sex chromosome evolution has increased over the past decade and is today a very active field. However, some areas within the field have not received as much attention as others. We therefore believe that a historic overview of key findings and empirical discoveries will put current thinking into context and help us better understand where to go next. Here, we present a timeline of important conceptual and analytical models, as well as empirical studies that have advanced the field and changed our understanding of the evolution of sex chromosomes. Finally, we highlight gaps in our knowledge so far and propose some specific areas within the field that we recommend a greater focus on in the future, including the role of ecology in sex chromosome evolution and new multilocus models of sex chromosome divergence.
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Affiliation(s)
- Jessica K Abbott
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
| | - Anna K Nordén
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
| | - Bengt Hansson
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
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13
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Veller C, Muralidhar P, Constable GWA, Nowak MA. Drift-Induced Selection Between Male and Female Heterogamety. Genetics 2017; 207:711-727. [PMID: 28821587 PMCID: PMC5629334 DOI: 10.1534/genetics.117.300151] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/15/2017] [Indexed: 12/18/2022] Open
Abstract
Evolutionary transitions between male and female heterogamety are common in both vertebrates and invertebrates. Theoretical studies of these transitions have found that, when all genotypes are equally fit, continuous paths of intermediate equilibria link the two sex chromosome systems. This observation has led to a belief that neutral evolution along these paths can drive transitions, and that arbitrarily small fitness differences among sex chromosome genotypes can determine the system to which evolution leads. Here, we study stochastic evolutionary dynamics along these equilibrium paths. We find non-neutrality, both in transitions retaining the ancestral pair of sex chromosomes, and in those creating a new pair. In fact, substitution rates are biased in favor of dominant sex determining chromosomes, which fix with higher probabilities than mutations of no effect. Using diffusion approximations, we show that this non-neutrality is a result of "drift-induced selection" operating at every point along the equilibrium paths: stochastic jumps off the paths return with, on average, a directional bias in favor of the dominant segregating sex chromosome. Our results offer a novel explanation for the observed preponderance of dominant sex determining genes, and hint that drift-induced selection may be a common force in standard population genetic systems.
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Affiliation(s)
- Carl Veller
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
- Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts 02138
| | - Pavitra Muralidhar
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
| | - George W A Constable
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, 8057, Switzerland
- Department of Mathematical Sciences, University of Bath, BA2 7AY, United Kingdom
| | - Martin A Nowak
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
- Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts 02138
- Department of Mathematics, Harvard University, Cambridge, Massachusetts 02138
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14
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Reduced Activity of SRY and its Target Enhancer Sox9-TESCO in a Mouse Species with X*Y Sex Reversal. Sci Rep 2017; 7:41378. [PMID: 28155866 PMCID: PMC5290746 DOI: 10.1038/srep41378] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/20/2016] [Indexed: 02/06/2023] Open
Abstract
In most eutherian mammals, sex determination is governed by the Y-linked gene Sry, but in African pygmy mice Mus minutoides, Sry action is overridden by a variant X chromosome (X*), yielding X*Y females. We hypothesized that X*Y sex reversal may be underpinned not only by neomorphic X chromosome functionality, but also by a compromised Sry pathway. Here, we show that neither M. minutoides SRY nor its target, the Sox9-TESCO enhancer, had appreciable transcriptional activity in in vitro assays, correlating with sequence degradation compared to Mus musculus counterparts. However, M. minutoides SRY activated its cognate TESCO to a moderate degree, and can clearly engage the male pathway in M. minutoides in the wild, indicating that SRY and TESCO may have co-evolved in M. minutoides to retain function above a threshold level. We suggest that weakening of the SRY/TESCO nexus may have facilitated the rise and spread of a variant X* chromosome carrying female-inducing modifier gene(s).
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15
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Charlesworth D. Plant contributions to our understanding of sex chromosome evolution. THE NEW PHYTOLOGIST 2015; 208:52-65. [PMID: 26053356 DOI: 10.1111/nph.13497] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/01/2015] [Indexed: 05/06/2023]
Abstract
A minority of angiosperms have male and female flowers separated in distinct individuals (dioecy), and most dioecious plants do not have cytologically different (heteromorphic) sex chromosomes. Plants nevertheless have several advantages for the study of sex chromosome evolution, as genetic sex determination has evolved repeatedly and is often absent in close relatives. I review sex-determining regions in non-model plant species, which may help us to understand when and how (and, potentially, test hypotheses about why) recombination suppression evolves within young sex chromosomes. I emphasize high-throughput sequencing approaches that are increasingly being applied to plants to test for non-recombining regions. These data are particularly illuminating when combined with sequence data that allow phylogenetic analyses, and estimates of when these regions evolved. Together with comparative genetic mapping, this has revealed that sex-determining loci and sex-linked regions evolved independently in many plant lineages, sometimes in closely related dioecious species, and often within the past few million years. In reviewing recent progress, I suggest areas for future work, such as the use of phylogenies to allow the informed choice of outgroup species suitable for inferring the directions of changes, including testing whether Y chromosome-like regions are undergoing genetic degeneration, a predicted consequence of losing recombination.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Lab, King's Buildings, W. Mains Road, Edinburgh, EH9 3FL, UK
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16
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Charlesworth D. The status of supergenes in the 21st century: recombination suppression in Batesian mimicry and sex chromosomes and other complex adaptations. Evol Appl 2015; 9:74-90. [PMID: 27087840 PMCID: PMC4780387 DOI: 10.1111/eva.12291] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/16/2015] [Indexed: 02/06/2023] Open
Abstract
I review theoretical models for the evolution of supergenes in the cases of Batesian mimicry in butterflies, distylous plants and sex chromosomes. For each of these systems, I outline the genetic evidence that led to the proposal that they involve multiple genes that interact during ‘complex adaptations’, and at which the mutations involved are not unconditionally advantageous, but show advantages that trade‐off against some disadvantages. I describe recent molecular genetic studies of these systems and questions they raise about the evolution of suppressed recombination. Nonrecombining regions of sex chromosomes have long been known, but it is not yet fully understood why recombination suppression repeatedly evolved in systems in distantly related taxa, but does not always evolve. Recent studies of distylous plants are tending to support the existence of recombination‐suppressed genome regions, which may include modest numbers of genes and resemble recently evolved sex‐linked regions. For Batesian mimicry, however, molecular genetic work in two butterfly species suggests a new supergene scenario, with a single gene mutating to produce initial adaptive phenotypes, perhaps followed by modifiers specifically refining and perfecting the new phenotype.
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17
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Sander van Doorn G. Patterns and mechanisms of evolutionary transitions between genetic sex-determining systems. Cold Spring Harb Perspect Biol 2014; 6:cshperspect.a017681. [PMID: 24993578 DOI: 10.1101/cshperspect.a017681] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The diversity and patchy phylogenetic distribution of genetic sex-determining mechanisms observed in some taxa is thought to have arisen by the addition, modification, or replacement of regulators at the upstream end of the sex-determining pathway. Here, I review the various evolutionary forces acting on upstream regulators of sexual development that can cause transitions between sex-determining systems. These include sex-ratio selection and pleiotropic benefits, as well as indirect selection mechanisms involving sex-linked sexually antagonistic loci or recessive deleterious mutations. Most of the current theory concentrates on the population-genetic aspects of sex-determination transitions, using models that do not reflect the developmental mechanisms involved in sex determination. However, the increasing availability of molecular data creates opportunities for the development of mechanistic models that can clarify how selection and developmental architecture interact to direct the evolution of sex-determination genes.
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Affiliation(s)
- G Sander van Doorn
- Centre for Ecological and Evolutionary Studies, University of Groningen, 9700 CC Groningen, The Netherlands
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18
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Saunders PA, Perez J, Rahmoun M, Ronce O, Crochet PA, Veyrunes F. XY females do better than the XX in the African pygmy mouse, Mus minutoides. Evolution 2014; 68:2119-27. [PMID: 24611447 DOI: 10.1111/evo.12387] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 02/08/2014] [Indexed: 12/11/2022]
Abstract
All therian mammals have a similar XY/XX sex-determination system except for a dozen species. The African pygmy mouse, Mus minutoides, harbors an unconventional system in which all males are XY, and there are three types of females: the usual XX but also XX* and X*Y ones (the asterisk designates a sex-reversal mutation on the X chromosome). The long-term evolution of such a system is a paradox, because X*Y females are expected to face high reproductive costs (e.g., meiotic disruption and loss of unviable YY embryos), which should prevent invasion and maintenance of a sex-reversal mutation. Hence, mechanisms for compensating for the costs could have evolved in M. minutoides. Data gathered from our laboratory colony revealed that X*Y females do compensate and even show enhanced reproductive performance in comparison to the XX and XX*; they produce significantly more offspring due to (i) a higher probability of breeding, (ii) an earlier first litter, and (iii) a larger litter size, linked to (iv) a greater ovulation rate. These findings confirm that rare conditions are needed for an atypical sex-determination mechanism to evolve in mammals, and provide valuable insight into understanding modifications of systems with highly heteromorphic sex chromosomes.
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Affiliation(s)
- Paul A Saunders
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554, Université Montpellier II, Montpellier, France.
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19
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van Doorn GS. Evolutionary transitions between sex-determining mechanisms: a review of theory. Sex Dev 2013; 8:7-19. [PMID: 24335102 DOI: 10.1159/000357023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The extraordinary diversity of sex-determining mechanisms found in nature is thought to have arisen by the addition, modification or replacement of regulators at the upstream end of the sex-determining pathway. The spread of a novel regulator of sex determination can manifest itself by an evolutionary transition between environmental and genetic sex determination, for example, or between male and female heterogamety. Both kinds of transition have occurred frequently in the course of evolution. In this paper, various evolutionary forces acting on sex-determining mutations that can bias transitions in one direction or the other are reviewed. Furthermore, the adaptive significance of the main modes of sex determination are discussed, and the common principle underlying ultimate explanations for environmental sex determination, genetic sex determination and maternal control over sex determination in the offspring are highlighted. Most of the current theory concentrates on the population-genetic aspects of sex determination transitions, using models that do not reflect the developmental mechanisms involved in sex determination. However, the increasing availability of molecular data creates opportunities for the future development of mechanistic models that will further clarify how selection and developmental architecture interact to direct the evolution of sex determination genes.
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Affiliation(s)
- G S van Doorn
- Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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20
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Maan ME, Sefc KM. Colour variation in cichlid fish: developmental mechanisms, selective pressures and evolutionary consequences. Semin Cell Dev Biol 2013; 24:516-28. [PMID: 23665150 PMCID: PMC3778878 DOI: 10.1016/j.semcdb.2013.05.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 04/15/2013] [Accepted: 05/01/2013] [Indexed: 12/17/2022]
Abstract
Cichlid fishes constitute one of the most species-rich families of vertebrates. In addition to complex social behaviour and morphological versatility, they are characterised by extensive diversity in colouration, both within and between species. Here, we review the cellular and molecular mechanisms underlying colour variation in this group and the selective pressures responsible for the observed variation. We specifically address the evidence for the hypothesis that divergence in colouration is associated with the evolution of reproductive isolation between lineages. While we conclude that cichlid colours are excellent models for understanding the role of animal communication in species divergence, we also identify taxonomic and methodological biases in the current research effort. We suggest that the integration of genomic approaches with ecological and behavioural studies, across the entire cichlid family and beyond it, will contribute to the utility of the cichlid model system for understanding the evolution of biological diversity.
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Affiliation(s)
- Martine E. Maan
- University of Groningen, Behavioural Biology, PO Box 11103, 9700 CC Groningen, The Netherlands
| | - Kristina M. Sefc
- Institute of Zoology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
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21
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Kikuchi K, Hamaguchi S. Novel sex-determining genes in fish and sex chromosome evolution. Dev Dyn 2013; 242:339-53. [PMID: 23335327 DOI: 10.1002/dvdy.23927] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 12/25/2012] [Accepted: 12/26/2012] [Indexed: 12/13/2022] Open
Abstract
Although the molecular mechanisms underlying many developmental events are conserved across vertebrate taxa, the lability at the top of the sex-determining (SD) cascade has been evident from the fact that four master SD genes have been identified: mammalian Sry; chicken DMRT1; medaka Dmy; and Xenopus laevis DM-W. This diversity is thought to be associated with the turnover of sex chromosomes, which is likely to be more frequent in fishes and other poikilotherms than in therian mammals and birds. Recently, four novel candidates for vertebrate SD genes were reported, all of them in fishes. These include amhy in the Patagonian pejerrey, Gsdf in Oryzias luzonensis, Amhr2 in fugu and sdY in rainbow trout. These studies provide a good opportunity to infer patterns from the seemingly chaotic picture of sex determination systems. Here, we review recent advances in our understanding of the master SD genes in fishes.
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Affiliation(s)
- Kiyoshi Kikuchi
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan.
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22
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Kamiya T, Kai W, Tasumi S, Oka A, Matsunaga T, Mizuno N, Fujita M, Suetake H, Suzuki S, Hosoya S, Tohari S, Brenner S, Miyadai T, Venkatesh B, Suzuki Y, Kikuchi K. A trans-species missense SNP in Amhr2 is associated with sex determination in the tiger pufferfish, Takifugu rubripes (fugu). PLoS Genet 2012; 8:e1002798. [PMID: 22807687 PMCID: PMC3395601 DOI: 10.1371/journal.pgen.1002798] [Citation(s) in RCA: 344] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/15/2012] [Indexed: 11/26/2022] Open
Abstract
Heterogametic sex chromosomes have evolved independently in various lineages of vertebrates. Such sex chromosome pairs often contain nonrecombining regions, with one of the chromosomes harboring a master sex-determining (SD) gene. It is hypothesized that these sex chromosomes evolved from a pair of autosomes that diverged after acquiring the SD gene. By linkage and association mapping of the SD locus in fugu (Takifugu rubripes), we show that a SNP (C/G) in the anti-Müllerian hormone receptor type II (Amhr2) gene is the only polymorphism associated with phenotypic sex. This SNP changes an amino acid (His/Asp384) in the kinase domain. While females are homozygous (His/His384), males are heterozygous. Sex in fugu is most likely determined by a combination of the two alleles of Amhr2. Consistent with this model, the medaka hotei mutant carrying a substitution in the kinase domain of Amhr2 causes a female phenotype. The association of the Amhr2 SNP with phenotypic sex is conserved in two other species of Takifugu but not in Tetraodon. The fugu SD locus shows no sign of recombination suppression between X and Y chromosomes. Thus, fugu sex chromosomes represent an unusual example of proto–sex chromosomes. Such undifferentiated X-Y chromosomes may be more common in vertebrates than previously thought. Diverse systems of sex determination have evolved independently in the animal and plant kingdoms. In vertebrates, so far four master sex-determining (SD) genes, Sry, Dmrt1, Dmy, and Dm-W, have been identified. These genes code for transcription factors and are located on only one of the sex chromosomes surrounded by nonrecombining regions. It is hypothesized that these sex chromosomes evolved from a pair of homologous chromosomes that diverged after acquiring the SD gene. We investigated the SD locus in fugu by high-resolution genetic mapping and association mapping. We found that a SNP that changes an amino acid (His/Asp384) in the kinase domain of anti-Müllerian hormone receptor type II (Amhr2) is perfectly associated with phenotypic sex. A combination of the two alleles of the SNP (homozygous females and heterozygous males) is likely to be responsible for sex determination in fugu. While these alleles are conserved in two other species of Takifugu, they are absent in the freshwater pufferfish, Tetraodon. Furthermore, Fugu Amhr2 lies in a region that shows no evidence for recombination suppression between X and Y chromosomes. Thus, fugu sex chromosomes represent an unusual example of a pre-differentiated phase of sex chromosomes in vertebrates.
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Affiliation(s)
- Takashi Kamiya
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Wataru Kai
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Satoshi Tasumi
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Ayumi Oka
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | | | - Naoki Mizuno
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Masashi Fujita
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Hiroaki Suetake
- Department of Marine Bioscience, Fukui Prefectural University, Obama, Fukui, Japan
| | - Shigenori Suzuki
- National Research Institute of Aquaculture, Fisheries Research Agency, Minamiizu, Shizuoka, Japan
| | - Sho Hosoya
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Sumanty Tohari
- Institute of Molecular and Cell Biology, A*STAR, Biopolis, Singapore, Singapore
| | - Sydney Brenner
- Institute of Molecular and Cell Biology, A*STAR, Biopolis, Singapore, Singapore
| | - Toshiaki Miyadai
- Department of Marine Bioscience, Fukui Prefectural University, Obama, Fukui, Japan
| | - Byrappa Venkatesh
- Institute of Molecular and Cell Biology, A*STAR, Biopolis, Singapore, Singapore
| | - Yuzuru Suzuki
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
| | - Kiyoshi Kikuchi
- Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, Japan
- * E-mail:
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MacCarthy T, Seymour RM, Pomiankowski A. Differential regulation drives plasticity in sex determination gene networks. BMC Evol Biol 2010; 10:388. [PMID: 21162741 PMCID: PMC3022605 DOI: 10.1186/1471-2148-10-388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 12/16/2010] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Sex determination networks evolve rapidly and have been studied intensely across many species, particularly in insects, thus presenting good models to study the evolutionary plasticity of gene networks. RESULTS We study the evolution of an unlinked gene capable of regulating an existing diploid sex determination system. Differential gene expression determines phenotypic sex and fitness, dramatically reducing the number of assumptions of previous models. It allows us to make a quantitative evaluation of the full range of evolutionary outcomes of the system and an assessment of the likely contribution of sexual conflict to change in sex determination systems. Our results show under what conditions network mutations causing differential regulation can lead to the reshaping of sex determination networks. CONCLUSION The analysis demonstrates the complex relationship between mutation and outcome: the same mutation can produce many different evolved populations, while the same evolved population can be produced by many different mutations. Existing network structure alters the constraints and frequency of evolutionary changes, which include the recruitment of new regulators, changes in heterogamety, protected polymorphisms, and transitions to a new locus that controls sex determination.
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Bewick AJ, Anderson DW, Evans BJ. EVOLUTION OF THE CLOSELY RELATED, SEX-RELATED GENES DM-W AND DMRT1 IN AFRICAN CLAWED FROGS (XENOPUS). Evolution 2010; 65:698-712. [DOI: 10.1111/j.1558-5646.2010.01163.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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25
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Charlesworth D, Mank JE. The birds and the bees and the flowers and the trees: lessons from genetic mapping of sex determination in plants and animals. Genetics 2010; 186:9-31. [PMID: 20855574 PMCID: PMC2940314 DOI: 10.1534/genetics.110.117697] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The ability to identify genetic markers in nonmodel systems has allowed geneticists to construct linkage maps for a diversity of species, and the sex-determining locus is often among the first to be mapped. Sex determination is an important area of study in developmental and evolutionary biology, as well as ecology. Its importance for organisms might suggest that sex determination is highly conserved. However, genetic studies have shown that sex determination mechanisms, and the genes involved, are surprisingly labile. We review studies using genetic mapping and phylogenetic inferences, which can help reveal evolutionary pattern within this lability and potentially identify the changes that have occurred among different sex determination systems. We define some of the terminology, particularly where confusion arises in writing about such a diverse range of organisms, and highlight some major differences between plants and animals, and some important similarities. We stress the importance of studying taxa suitable for testing hypotheses, and the need for phylogenetic studies directed to taxa where the patterns of changes can be most reliably inferred, if the ultimate goal of testing hypotheses regarding the selective forces that have led to changes in such an essential trait is to become feasible.
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Affiliation(s)
- Deborah Charlesworth
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford OX1 3PS, United Kingdom.
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26
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Abstract
Many animal taxa show frequent and rapid transitions between male heterogamety (XY) and female heterogamety (ZW). We develop a model showing how these transitions can be driven by sex-antagonistic selection. Sex-antagonistic selection acting on loci linked to a new sex-determination mutation can cause it to invade, but when acting on loci linked to the ancestral sex-determination gene will inhibit an invasion. The strengths of the consequent indirect selection on the old and new sex-determination loci are mediated by the strengths of sex-antagonistic selection, linkage between the sex-antagonistic and sex-determination genes, and the amount of genetic variation. Sex-antagonistic loci that are tightly linked to a sex-determining gene have a vastly stronger influence on the balance of selection than more distant loci. As a result, changes in linkage, caused, for example, by an inversion that captures a sex-determination mutation and a gene under sex-antagonistic selection, can trigger transitions between XY and ZW systems. Sex-antagonistic alleles can become more strongly associated with pleiotropically dominant sex-determining factors, which may help to explain biases in the rates of transitions between male and female heterogamety. Deleterious recessive mutations completely linked to the ancestral Y chromosome can prevent invasion of a neo-W chromosome or result in a stable equilibrium at which XY and ZW systems segregate simultaneously at two linkage groups.
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27
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STELKENS RIKEB, WEDEKIND CLAUS. Environmental sex reversal, Trojan sex genes, and sex ratio adjustment: conditions and population consequences. Mol Ecol 2010; 19:627-46. [DOI: 10.1111/j.1365-294x.2010.04526.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Veyrunes F, Chevret P, Catalan J, Castiglia R, Watson J, Dobigny G, Robinson TJ, Britton-Davidian J. A novel sex determination system in a close relative of the house mouse. Proc Biol Sci 2009; 277:1049-56. [PMID: 20007182 DOI: 10.1098/rspb.2009.1925] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Therian mammals have an extremely conserved XX/XY sex determination system. A limited number of mammal species have, however, evolved to escape convention and present aberrant sex chromosome complements. In this study, we identified a new case of atypical sex determination in the African pygmy mouse Mus minutoides, a close evolutionary relative of the house mouse. The pygmy mouse is characterized by a very high proportion of XY females (74%, n = 27) from geographically widespread Southern and Eastern African populations. Sequencing of the high mobility group domain of the mammalian sex determining gene Sry, and karyological analyses using fluorescence in situ hybridization and G-banding data, suggest that the sex reversal is most probably not owing to a mutation of Sry, but rather to a chromosomal rearrangement on the X chromosome. In effect, two morphologically different X chromosomes were identified, one of which, designated X*, is invariably associated with sex-reversed females. The asterisk designates the still unknown mutation converting X*Y individuals into females. Although relatively still unexplored, such an atypical sex chromosome system offers a unique opportunity to unravel new genetic interactions involved in the initiation of sex determination in mammals.
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Affiliation(s)
- Frederic Veyrunes
- Institut des Sciences de l'Evolution (UMR CNRS/Université Montpellier II), Montpellier, France.
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Ser JR, Roberts RB, Kocher TD. Multiple interacting loci control sex determination in lake Malawi cichlid fish. Evolution 2009; 64:486-501. [PMID: 19863587 DOI: 10.1111/j.1558-5646.2009.00871.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Several models have been proposed to suggest how the evolution of sex-determining mechanisms might contribute to speciation. Here, we describe the inheritance of sex in 19 fish species from the rapidly evolving flock of cichlids in Lake Malawi, Africa. We found that many of these species have a male heterogametic (XY) system on linkage group 7. Some species also segregate for a female heterogametic (ZW) system on linkage group 5 that is coincident with a dominant orange-blotch (OB) color pattern in females. The ZW system is epistatically dominant to the XY system when both are segregating within a family. Several lines of evidence suggest that additional sex-determining loci are segregating in some species. These results are consistent with the idea that genetic conflicts play an important role in the evolution of these species flocks and suggest that evolution of sex-determining mechanisms has contributed to the radiation of cichlid fish in East Africa.
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Affiliation(s)
- Jennifer R Ser
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
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30
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Turnover of sex chromosomes induced by sexual conflict. Nature 2007; 449:909-12. [DOI: 10.1038/nature06178] [Citation(s) in RCA: 282] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 08/17/2007] [Indexed: 11/09/2022]
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