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Abstract
Disruptive selection between males and females can generate sexual antagonism, where alleles improving fitness in one sex reduce fitness in the other. This type of genetic conflict arises because males and females carry nearly identical sets of genes: opposing selection, followed by genetic mixing during reproduction, generates a population genetic "tug-of-war" that constrains adaptation in either sex. Recent verbal models suggest that gene duplication and sex-specific cooption of paralogs might resolve sexual antagonism and facilitate evolutionary divergence between the sexes. However, this intuitive proximal solution for sexual dimorphism potentially belies a complex interaction between mutation, genetic drift, and positive selection during duplicate fixation and sex-specific paralog differentiation. The interaction of these processes--within the explicit context of duplication and sexual antagonism--has yet to be formally described by population genetics theory. Here, we develop and analyze models of gene duplication and sex-specific differentiation between paralogs. We show that sexual antagonism can favor the fixation and maintenance of gene duplicates, eventually leading to the evolution of sexually dimorphic genetic architectures for male and female traits. The timescale for these evolutionary transitions is sensitive to a suite of genetic and demographic variables, including allelic dominance, recombination, sex linkage, and population size. Interestingly, we find that female-beneficial duplicates preferentially accumulate on the X chromosome, whereas male-beneficial duplicates are biased toward autosomes, independent of the dominance parameters of sexually antagonistic alleles. Although this result differs from previous models of sexual antagonism, it is consistent with several findings from the empirical genomics literature.
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202
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Snell-Rood EC, Cash A, Han MV, Kijimoto T, Andrews J, Moczek AP. Developmental decoupling of alternative phenotypes: insights from the transcriptomes of horn-polyphenic beetles. Evolution 2011; 65:231-45. [PMID: 20731717 PMCID: PMC3010270 DOI: 10.1111/j.1558-5646.2010.01106.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Developmental mechanisms play an important role in determining the costs, limits, and evolutionary consequences of phenotypic plasticity. One issue central to these claims is the hypothesis of developmental decoupling, where alternate morphs result from evolutionarily independent developmental pathways. We address this assumption through a microarray study that tests whether differences in gene expression between alternate morphs are as divergent as those between sexes, a classic example of developmental decoupling. We then examine whether genes with morph-biased expression are less conserved than genes with shared expression between morphs, as predicted if developmental decoupling relaxes pleiotropic constraints on divergence. We focus on the developing horns and brains of two species of horned beetles with impressive sexual- and morph-dimorphism in the expression of horns and fighting behavior. We find that patterns of gene expression were as divergent between morphs as they were between sexes. However, overall patterns of gene expression were also highly correlated across morphs and sexes. Morph-biased genes were more evolutionarily divergent, suggesting a role of relaxed pleiotropic constraints or relaxed selection. Together these results suggest that alternate morphs are to some extent developmentally decoupled, and that this decoupling has significant evolutionary consequences. However, alternative morphs may not be as developmentally decoupled as sometimes assumed and such hypotheses of development should be revisited and refined.
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Affiliation(s)
- Emilie C Snell-Rood
- Department of Biology, Indiana University, 915 E. Third Street, Myers Hall 150, Bloomington, Indiana 47405-7107, USA.
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203
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Gallou-Kabani C, Gabory A, Tost J, Karimi M, Mayeur S, Lesage J, Boudadi E, Gross MS, Taurelle J, Vigé A, Breton C, Reusens B, Remacle C, Vieau D, Ekström TJ, Jais JP, Junien C. Sex- and diet-specific changes of imprinted gene expression and DNA methylation in mouse placenta under a high-fat diet. PLoS One 2010; 5:e14398. [PMID: 21200436 PMCID: PMC3006175 DOI: 10.1371/journal.pone.0014398] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 11/26/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Changes in imprinted gene dosage in the placenta may compromise the prenatal control of nutritional resources. Indeed monoallelic behaviour and sensitivity to changes in regional epigenetic state render imprinted genes both vulnerable and adaptable. METHODS AND FINDINGS We investigated whether a high-fat diet (HFD) during pregnancy modified the expression of imprinted genes and local and global DNA methylation patterns in the placenta. Pregnant mice were fed a HFD or a control diet (CD) during the first 15 days of gestation. We compared gene expression patterns in total placenta homogenates, for male and female offspring, by the RT-qPCR analysis of 20 imprinted genes. Sexual dimorphism and sensitivity to diet were observed for nine genes from four clusters on chromosomes 6, 7, 12 and 17. As assessed by in situ hybridization, these changes were not due to variation in the proportions of the placental layers. Bisulphite-sequencing analysis of 30 CpGs within the differentially methylated region (DMR) of the chromosome 17 cluster revealed sex- and diet-specific differential methylation of individual CpGs in two conspicuous subregions. Bioinformatic analysis suggested that these differentially methylated CpGs might lie within recognition elements or binding sites for transcription factors or factors involved in chromatin remodelling. Placental global DNA methylation, as assessed by the LUMA technique, was also sexually dimorphic on the CD, with lower methylation levels in male than in female placentae. The HFD led to global DNA hypomethylation only in female placenta. Bisulphite pyrosequencing showed that neither B1 nor LINE repetitive elements could account for these differences in DNA methylation. CONCLUSIONS A HFD during gestation triggers sex-specific epigenetic alterations within CpG and throughout the genome, together with the deregulation of clusters of imprinted genes important in the control of many cellular, metabolic and physiological functions potentially involved in adaptation and/or evolution. These findings highlight the importance of studying both sexes in epidemiological protocols and dietary interventions.
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Affiliation(s)
- Catherine Gallou-Kabani
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
| | - Anne Gabory
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
- INRA, UMR1198, UMR INRA/ENV Maisons-Alfort/CNRS: Biologie du Développement et Reproduction, (ENV Maisons-Alfort; CNRS), Physiologie Animale et Systèmes d'Elevage, Centre de recherche de Jouy-en-Josas, Jouy-en-Josas, France
| | - Jörg Tost
- Laboratoire d'Epigénétique, CEA - Institut de Génomique, Centre National de Génotypage, Evry, France
| | - Mohsen Karimi
- Laboratory for Medical Epigenetics, Department of Clinical Neuroscience, Centre for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Sylvain Mayeur
- Unité Environnement Périnatal et Croissance, EA 4489, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | - Jean Lesage
- Unité Environnement Périnatal et Croissance, EA 4489, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | - Elsa Boudadi
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
| | - Marie-Sylvie Gross
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
| | - Julien Taurelle
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
| | - Alexandre Vigé
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
| | - Christophe Breton
- Unité Environnement Périnatal et Croissance, EA 4489, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | - Brigitte Reusens
- Laboratory of Cell Biology, Institute of Life Sciences, Catholic University of Louvain, Louvain-la-Neuve, Belgium
| | - Claude Remacle
- Laboratory of Cell Biology, Institute of Life Sciences, Catholic University of Louvain, Louvain-la-Neuve, Belgium
| | - Didier Vieau
- Unité Environnement Périnatal et Croissance, EA 4489, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
| | - Tomas J. Ekström
- Laboratory for Medical Epigenetics, Department of Clinical Neuroscience, Centre for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Claudine Junien
- Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, U781, Paris, France
- INRA, UMR1198, UMR INRA/ENV Maisons-Alfort/CNRS: Biologie du Développement et Reproduction, (ENV Maisons-Alfort; CNRS), Physiologie Animale et Systèmes d'Elevage, Centre de recherche de Jouy-en-Josas, Jouy-en-Josas, France
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204
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Connallon T, Clark AG. Sex linkage, sex-specific selection, and the role of recombination in the evolution of sexually dimorphic gene expression. Evolution 2010; 64:3417-42. [PMID: 20874735 PMCID: PMC2998557 DOI: 10.1111/j.1558-5646.2010.01136.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sex-biased genes--genes that are differentially expressed within males and females--are nonrandomly distributed across animal genomes, with sex chromosomes and autosomes often carrying markedly different concentrations of male- and female-biased genes. These linkage patterns are often gene- and lineage-dependent, differing between functional genetic categories and between species. Although sex-specific selection is often hypothesized to shape the evolution of sex-linked and autosomal gene content, population genetics theory has yet to account for many of the gene- and lineage-specific idiosyncrasies emerging from the empirical literature. With the goal of improving the connection between evolutionary theory and a rapidly growing body of genome-wide empirical studies, we extend previous population genetics theory of sex-specific selection by developing and analyzing a biologically informed model that incorporates sex linkage, pleiotropy, recombination, and epistasis, factors that are likely to vary between genes and between species. Our results demonstrate that sex-specific selection and sex-specific recombination rates can generate, and are compatible with, the gene- and species-specific linkage patterns reported in the genomics literature. The theory suggests that sexual selection may strongly influence the architectures of animal genomes, as well as the chromosomal distribution of fixed substitutions underlying sexually dimorphic traits.
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Affiliation(s)
- Tim Connallon
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, New York 14853-2703, USA.
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205
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Chenoweth SF, McGuigan K. The Genetic Basis of Sexually Selected Variation. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2010. [DOI: 10.1146/annurev-ecolsys-102209-144657] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sexually selected traits contribute greatly to phenotypic diversity, yet we have historically understood little about their genetic basis and how that basis may affect their evolution. Recent work in developmental and quantitative genetics has provided both mechanistic and statistical descriptions of genotype-phenotype maps for sexually selected traits. These studies expose generally complex genetic architectures; genotype-phenotype maps are polygenic with allelic effects that are pleiotropic and highly context-dependent. At the same time, developments in quantitative genetics have provided new insights into the microevolutionary potential of standing variation and indicate genetic constraints on the contemporary evolution of male sexually selected characters, mate preferences, and also male mating success itself. Understanding the extent to which these constraints are a function of genetic architecture will require a tighter integration of developmental, molecular, and quantitative genetic approaches in a variety of model systems. Emerging genomic technologies offer an unprecedented opportunity to deepen our understanding of sexual selection as an evolutionary process.
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Affiliation(s)
- Stephen F. Chenoweth
- School of Biological Sciences, The University of Queensland, St Lucia 4072, Australia
| | - Katrina McGuigan
- School of Biological Sciences, The University of Queensland, St Lucia 4072, Australia
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206
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Abstract
The processes governing the evolution of sexual dimorphism provided a foundation for sexual selection theory. Two alternative processes, originally proposed by Darwin and Wallace, differ primarily in the timing of events creating the dimorphism. In the process advocated by Darwin, a novel ornament arises in a single sex, with no temporal separation in the origin and sex-limitation of the novel trait. By contrast, Wallace proposed a process where novel ornaments appear simultaneously in both sexes, but are then converted into sex-limited expression by natural selection acting against showy coloration in one sex. Here, we investigate these alternative modes of sexual dimorphism evolution in a phylogenetic framework and demonstrate that both processes contribute to dimorphic wing patterns in the butterfly genera Bicyclus and Junonia. In some lineages, eyespots and bands arise in a single sex, whereas in other lineages they appear in both sexes but are then lost in one of the sexes. In addition, lineages displaying sexual dimorphism were more likely to become sexually monomorphic than they were to remain dimorphic. This derived monomorphism was either owing to a loss of the ornament ('drab monomorphism') or owing to a gain of the same ornament by the opposite sex ('mutual ornamentation'). Our results demonstrate the necessity of a plurality in theories explaining the evolution of sexual dimorphism within and across taxa. The origins and evolutionary fate of sexual dimorphism are probably influenced by underlying genetic architecture responsible for sex-limited expression and the degree of intralocus sexual conflict. Future comparative and developmental work on sexual dimorphism within and among taxa will provide a better understanding of the biases and constraints governing the evolution of animal sexual dimorphism.
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Affiliation(s)
- Jeffrey C Oliver
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA.
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207
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Heritability and genetic correlation between the sexes in a songbird sexual ornament. Heredity (Edinb) 2010; 106:945-54. [PMID: 21081966 DOI: 10.1038/hdy.2010.142] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genetic correlation between the sexes in the expression of secondary sex traits in wild vertebrate populations has attracted very few previous empirical efforts of field researchers. In southern European populations of pied flycatchers, a sexually selected male ornament is also expressed by a proportion of females. Additive genetic variances in ornament size and expression, transmission mechanisms (autosomal vs Z-linkage) and maternal effects are examined by looking at patterns of familial resemblance across three generations. Size of the secondary sex trait has a genetic basis common to both sexes, with estimated heritability being 0.5 under an autosomal model of inheritance. Significant additive genetic variance in males was also confirmed through a cross-fostering experiment. Heritability analyses were only partially consistent with previous molecular genetics evidence, as only two out of the three predictions supported Z-linkage and lack of significant mother-daughter resemblance could be due to small sample sizes caused by limited female trait expression. Therefore, the evidence was mixed as to the contribution of the Z chromosome and autosomal genes to trait size. The threshold heritability of trait expression in females was lower, around 0.3, supporting autosomal-based trait expression in females. Environmental (birth date) and parental effects on ornament size mediated by the mother's condition after accounting for maternal and paternal genetic influences are also highlighted. The genetic correlation between the sexes did not differ from one, indicating that selection on the character on either sex entails a correlated response in the opposite sex.
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208
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Morgan DE, Crittenden SL, Kimble J. The C. elegans adult male germline: stem cells and sexual dimorphism. Dev Biol 2010; 346:204-14. [PMID: 20659446 PMCID: PMC2945412 DOI: 10.1016/j.ydbio.2010.07.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/14/2010] [Accepted: 07/18/2010] [Indexed: 01/07/2023]
Abstract
The hermaphrodite Caenorhabditis elegans germline has become a classic model for stem cell regulation, but the male C. elegans germline has been largely neglected. This work provides a cellular analysis of the adult C. elegans male germline, focusing on its predicted stem cell region in the distal gonad. The goals of this study were two-fold: to establish the C. elegans male germline as a stem cell model and to identify sex-specific traits of potential relevance to the sperm/oocyte decision. Our results support two major conclusions. First, adult males do indeed possess a population of germline stem cells (GSCs) with properties similar to those of hermaphrodite GSCs (lack of cell cycle quiescence and lack of reproducibly oriented divisions). Second, germ cells in the mitotic region, including those most distal within the niche, exhibit sex-specific behaviors (e.g. cell cycle length) and therefore have acquired sexual identity. Previous studies demonstrated that some germ cells are not committed to a sperm or oocyte cell fate, even in adults. We propose that germ cells can acquire sexual identity without being committed to a sperm or oocyte cell fate.
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Affiliation(s)
- Dyan E. Morgan
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Sarah L. Crittenden
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Judith Kimble
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706 USA
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209
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Zluvova J, Zak J, Janousek B, Vyskot B. Dioecious Silene latifolia plants show sexual dimorphism in the vegetative stage. BMC PLANT BIOLOGY 2010; 10:208. [PMID: 20854681 PMCID: PMC2956557 DOI: 10.1186/1471-2229-10-208] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 09/20/2010] [Indexed: 05/06/2023]
Abstract
BACKGROUND Prior to this study, no differences in gene expression between male and female dioecious plants in the vegetative state had been detected. Among dioecious plants displaying sexual dimorphism, Silene latifolia is one of the most studied species. Although many sexually dimorphic traits have been described in S. latifolia, all of them are quantitative, and they usually become apparent only after the initiation of flowering. RESULTS We present RT-PCR-based evidence that in S. latifolia, sexual dimorphism in gene expression is present long before the initiation of flowering. We describe three ESTs that show sex-specific (two male specific and one female specific) transcription at the rosette stage before the first flowering season. CONCLUSIONS To our knowledge, this study provides the first molecular evidence of early pre-flowering sexual dimorphism in angiosperms.
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Affiliation(s)
- Jitka Zluvova
- Department of Plant Developmental Genetics, Institute of Biophysics AS CR v. v. i., Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Jiri Zak
- Department of Plant Developmental Genetics, Institute of Biophysics AS CR v. v. i., Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Bohuslav Janousek
- Department of Plant Developmental Genetics, Institute of Biophysics AS CR v. v. i., Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, Institute of Biophysics AS CR v. v. i., Kralovopolska 135, 612 65 Brno, Czech Republic
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210
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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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211
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Rodríguez-Marí A, Cañestro C, BreMiller RA, Nguyen-Johnson A, Asakawa K, Kawakami K, Postlethwait JH. Sex reversal in zebrafish fancl mutants is caused by Tp53-mediated germ cell apoptosis. PLoS Genet 2010; 6:e1001034. [PMID: 20661450 PMCID: PMC2908690 DOI: 10.1371/journal.pgen.1001034] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 06/17/2010] [Indexed: 11/19/2022] Open
Abstract
The molecular genetic mechanisms of sex determination are not known for most vertebrates, including zebrafish. We identified a mutation in the zebrafish fancl gene that causes homozygous mutants to develop as fertile males due to female-to-male sex reversal. Fancl is a member of the Fanconi Anemia/BRCA DNA repair pathway. Experiments showed that zebrafish fancl was expressed in developing germ cells in bipotential gonads at the critical time of sexual fate determination. Caspase-3 immunoassays revealed increased germ cell apoptosis in fancl mutants that compromised oocyte survival. In the absence of oocytes surviving through meiosis, somatic cells of mutant gonads did not maintain expression of the ovary gene cyp19a1a and did not down-regulate expression of the early testis gene amh; consequently, gonads masculinized and became testes. Remarkably, results showed that the introduction of a tp53 (p53) mutation into fancl mutants rescued the sex-reversal phenotype by reducing germ cell apoptosis and, thus, allowed fancl mutants to become fertile females. Our results show that Fancl function is not essential for spermatogonia and oogonia to become sperm or mature oocytes, but instead suggest that Fancl function is involved in the survival of developing oocytes through meiosis. This work reveals that Tp53-mediated germ cell apoptosis induces sex reversal after the mutation of a DNA-repair pathway gene by compromising the survival of oocytes and suggests the existence of an oocyte-derived signal that biases gonad fate towards the female developmental pathway and thereby controls zebrafish sex determination.
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Affiliation(s)
- Adriana Rodríguez-Marí
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Cristian Cañestro
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Ruth A. BreMiller
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | | | - Kazuhide Asakawa
- Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies (Sokendai), Mishima, Shizuoka, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies (Sokendai), Mishima, Shizuoka, Japan
| | - John H. Postlethwait
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
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212
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Kalis AK, Murphy MW, Zarkower D. EGL-5/ABD-B plays an instructive role in male cell fate determination in the C. elegans somatic gonad. Dev Biol 2010; 344:827-35. [PMID: 20553900 DOI: 10.1016/j.ydbio.2010.05.516] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/26/2010] [Accepted: 05/28/2010] [Indexed: 01/15/2023]
Abstract
Hox genes of the Abdominal-B (Abd-B) class regulate gonadal development in diverse metazoans. Here we have investigated the role of the Abd-B homolog egl-5 in C. elegans gonadal development. Previous work showed that egl-5 is required male-specifically in the gonad and that mutant gonads are highly dysgenic and possibly feminized. We have used sex-specific gonadal reporter genes to confirm that the gonads of egl-5 males are extensively feminized. Sex-specific expression of egl-5 requires the global sex determination gene tra-1 and the gonadal masculinizing gene fkh-6, but mutagenesis of a short male gonadal enhancer element in egl-5 suggested that this regulation is indirect. Ectopic expression of EGL-5 in hermaphrodites is sufficient to induce male gonadal gene expression, indicating that EGL-5 plays an instructive role in male gonadal fate determination. EGL-5 acts in parallel with a Wnt/beta-catenin pathway to regulate male gonadal fates and can physically interact with the Wnt pathway transcription factor POP-1 and modulate activity of a POP-1 dependent reporter gene. We propose that EGL-5 imparts sex-specific function on POP-1 by recruiting it to male-specific gonadal target genes.
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Affiliation(s)
- Andrea K Kalis
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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213
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Casci T. Where sexes collide. Nat Rev Genet 2010; 11:316. [DOI: 10.1038/nrg2787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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214
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Ferris P, Olson BJ, De Hoff PL, Douglass S, Diaz-Cano DC, Prochnik S, Geng S, Rai R, Grimwood J, Schmutz J, Nishii I, Hamaji T, Nozaki H, Pellegrini M, Umen JG. Evolution of an expanded sex-determining locus in Volvox. Science 2010; 328:351-4. [PMID: 20395508 PMCID: PMC2880461 DOI: 10.1126/science.1186222] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Although dimorphic sexes have evolved repeatedly in multicellular eukaryotes, their origins are unknown. The mating locus (MT) of the sexually dimorphic multicellular green alga Volvox carteri specifies the production of eggs and sperm and has undergone a remarkable expansion and divergence relative to MT from Chlamydomonas reinhardtii, which is a closely related unicellular species that has equal-sized gametes. Transcriptome analysis revealed a rewired gametic expression program for Volvox MT genes relative to Chlamydomonas and identified multiple gender-specific and sex-regulated transcripts. The retinoblastoma tumor suppressor homolog MAT3 is a Volvox MT gene that displays sexually regulated alternative splicing and evidence of gender-specific selection, both of which are indicative of cooption into the sexual cycle. Thus, sex-determining loci affect the evolution of both sex-related and non-sex-related genes.
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Affiliation(s)
- Patrick Ferris
- The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | | | - Peter L. De Hoff
- The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Stephen Douglass
- Institute for Genomics and Proteomics and Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, 90095, USA
| | - David Casero Diaz-Cano
- Institute for Genomics and Proteomics and Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, 90095, USA
| | - Simon Prochnik
- U.S. Department of Energy (DOE) Joint Genome Institute (JGI), Walnut Creek, California, 95498, USA
| | - Sa Geng
- The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Rhitu Rai
- The Salk Institute for Biological Studies, La Jolla, California 92037, USA
- Laboratory of Plant Microbe Interaction, National Research Center on Plant Biotechnology, Pusa Campus, Indian Agricultural Research Institute, New Delhi-110012, India
| | - Jane Grimwood
- Genome Sequencing Center, Hudson Alpha Institute for Biotechnology, Huntsville, Alabama, 35906, USA
| | - Jeremy Schmutz
- Genome Sequencing Center, Hudson Alpha Institute for Biotechnology, Huntsville, Alabama, 35906, USA
| | - Ichiro Nishii
- Department of Biological Science, Nara Women's University, Nara 630-8506, Japan
| | - Takashi Hamaji
- Department of Biological Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Matteo Pellegrini
- Institute for Genomics and Proteomics and Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, 90095, USA
| | - James G. Umen
- The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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215
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Swami M. Male versus female. Nat Rev Genet 2010. [DOI: 10.1038/nrg2739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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216
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Erratum: Genetic and molecular insights into the development and evolution of sexual dimorphism. Nat Rev Genet 2009. [DOI: 10.1038/nrg2710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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217
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Babbitt CC, Silverman JS, Haygood R, Reininga JM, Rockman MV, Wray GA. Multiple Functional Variants in cis Modulate PDYN Expression. Mol Biol Evol 2009; 27:465-79. [PMID: 19910384 DOI: 10.1093/molbev/msp276] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Understanding genetic variation and its functional consequences within cis-regulatory regions remains an important challenge in human genetics and evolution. Here, we present a fine-scale functional analysis of segregating variation within the cis-regulatory region of prodynorphin, a gene that encodes an endogenous opioid precursor with roles in cognition and disease. In order to characterize the functional consequences of segregating variation in cis in a region under balancing selection in different human populations, we examined associations between specific polymorphisms and gene expression in vivo and in vitro. We identified five polymorphisms within the 5' flanking region that affect transcript abundance: a 68-bp repeat recognized in prior studies, as well as two microsatellites and two single nucleotide polymorphisms not previously implicated as functional variants. The impact of these variants on transcription differs by brain region, sex, and cell type, implying interactions between cis genotype and the differentiated state of cells. The effects of individual variants on expression level are not additive in some combinations, implying epistatic interactions between nearby variants. These data reveal an unexpectedly complex relationship between segregating genetic variation and its expression-trait consequences and highlights the importance of close functional scrutiny of natural genetic variation within even relatively well-studied cis-regulatory regions.
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218
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The means to discriminate. Nat Rev Genet 2009. [DOI: 10.1038/nrg2704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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