Dataset Information

Haploid Selection Favors Suppressed Recombination Between Sex Chromosomes Despite Causing Biased Sex Ratios.

ABSTRACT: To date, research on the evolution of sex chromosomes has focused on sexually antagonistic selection among diploids, which has been shown to be a potent driver of the strata and reduced recombination that characterize many sex chromosomes. However, significant selection can also occur on haploid genotypes during less conspicuous life cycle stages, e.g., competition among sperm/pollen or meiotic drive during gamete/spore production. These haploid selective processes are typically sex-specific, e.g., gametic/gametophytic competition typically occurs among sperm/pollen, and meiotic drive typically occurs during either spermatogenesis or oogenesis. We use models to investigate whether sex-specific selection on haploids could drive the evolution of recombination suppression on the sex chromosomes, as has been demonstrated for sex-specific selection among diploids. A potential complication is that zygotic sex-ratios become biased when haploid selected loci become linked to the sex-determining region because the zygotic sex ratio is determined by the relative number and fitness of X- vs. Y-bearing sperm. Despite causing biased zygotic sex-ratios, we find that a period of sex-specific haploid selection generally favors recombination suppression on the sex chromosomes. Suppressed recombination is favored because it allows associations to build up between haploid-beneficial alleles and the sex that experiences haploid selection most often (e.g., pollen beneficial alleles become strongly associated with the male determining region, Y or Z). Haploid selected loci can favor recombination suppression even in the absence of selective differences between male and female diploids. Overall, we expand our view of the sex-specific life cycle stages that can drive sex chromosome evolution to include gametic competition and meiotic drive. Based on our models, sex chromosomes should become enriched for genes that experience haploid selection, as is expected for genes that experience sexually antagonistic selection. Thus, we generate a number of predictions that can be evaluated in emerging sex chromosome systems.

SUBMITTER: Scott MF

PROVIDER: S-EPMC5714470 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Haploid Selection Favors Suppressed Recombination Between Sex Chromosomes Despite Causing Biased Sex Ratios.

Scott Michael F MF Otto Sarah P SP

Genetics 20171019 4

To date, research on the evolution of sex chromosomes has focused on sexually antagonistic selection among diploids, which has been shown to be a potent driver of the strata and reduced recombination that characterize many sex chromosomes. However, significant selection can also occur on haploid genotypes during less conspicuous life cycle stages, <i>e.g.</i>, competition among sperm/pollen or meiotic drive during gamete/spore production. These haploid selective processes are typically sex-speci ...[more]

PMID: 29051194

Similar Datasets

Project description:Chromosome rearrangements (CRs) are perceived to be related to sex chromosome evolution, but it is a matter of controversy whether CRs are the initial causative mechanism of suppressed recombination for sex differentiation. The early stages of sex chromosome evolution in amphibians may represent intermediate states of differentiation, and if so, they potentially shed light on the ultimate cause of suppressed recombination and the role of CRs in sex chromosome differentiation. In this paper, we showed that sex determination differs among 16 populations of spiny frog (Quasipaa boulengeri), in which individuals have normal and rearranged chromosomes caused by reciprocal translocation. In eastern areas, without translocation, genetic differentiation between sexes was relatively low, suggesting unrestricted recombination. In comparison, in western populations that have both normal and translocated chromosomes, a male-heterogametic system and lack of X-Y recombination were identified by male-specific alleles and heterozygote excess. However, such genetic differentiation between sexes in western populations was not directly related to karyotypes, as it was found in individuals with both normal and translocated karyotypes. In the western Sichuan Basin, male-specific and translocation-specific allelic frequency distributions suggested that recombination of sex-differentiation ceased in all populations, but recombination suppression caused by translocation did not exist in some populations. Combined with phylogenetic inference, this indicated that the establishment of sex-linkage had taken place independently of reciprocal translocation, and translocation was not the ultimate cause of sex chromosome differentiation. Furthermore, comparison of the genetic diversity of alleles on Y chromosomes, X chromosomes, and autosomes in western populations showed a reduction of effective population size on sex chromosomes, which may be caused by reciprocal translocation. It indicates that, although it is not the ultimate cause of recombination suppression, reciprocal translocation may enhance sex chromosome differentiation.

Dataset Information

Haploid Selection Favors Suppressed Recombination Between Sex Chromosomes Despite Causing Biased Sex Ratios.

Publications

Haploid Selection Favors Suppressed Recombination Between Sex Chromosomes Despite Causing Biased Sex Ratios.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets