Evolutionary Dynamics of Recombining Sex Chromosomes

 描述(由申请人提供) 从形态和行为到基因表达和疾病风险，男性和女性在生物组织的几乎所有层面上都存在着深刻的差异。塑造这些差异的一个关键力量是性对抗选择，即在一个性别中有益的基因在另一个性别中是有害的。这种类型的选择被认为推动了基因组的几个特征的进化，也被假设为人类疾病易感性的性别差异的基础。尽管它很重要，但我们几乎没有关于性对抗选择在基因组中起作用的直接信息，也没有关于它在造成性别差异方面的作用的直接信息。性染色体是研究性拮抗选择的最有前景的背景，因为它们被预测为经历这种类型选择的基因积累的热点。此外，性对抗选择被认为是性染色体独特性质的进化的罪魁祸首，例如X和Y之间的重组减少，以及随后Y的退化。然而，来自性染色体的许多现有数据来自于性染色体高度退化和基因贫乏的系统，使得识别经受性对抗选择的基因变得困难或不可能。刺鱼是一种新兴的模式系统，其性染色体仍然重组，并且富含基因，使它们非常适合研究性对立选择。这个研究项目将利用这些特性来了解性对抗选择是如何塑造染色体、基因和表型的。这三个主要目标将：(1)使用遗传学、细胞遗传学和基因组学工具来揭示X和Y染色体之间的重组是如何被抑制的；(2)获得全基因组序列，以研究男性和女性之间的许多差异如何改变基因和染色体的进化轨迹；以及(3)使用新的统计学方法来确定性别拮抗选择的遗传和表型目标。这个项目的结果将在刺鱼的性染色体以外的环境中发挥作用。它将产生技术创新，例如分析DNA变异的新统计方法，这将对研究不同类群中常染色体上的染色体重排有价值。此外，这项工作的洞察力将为选择建立对包括人类在内的所有物种的健康有害的基因的可能性提供视角。

 DESCRIPTION (provided by applicant) Males and females differ profoundly at virtually all levels of biological organization, from morphology and behavior to gene expression and disease risk. A key force that molds these differences is sexually antagonistic selection, in which a gene that is beneficial in one sex is detrimental in the other. This type of selection is thought to drive the evolution of several features of the genome, and it has also been hypothesized to underlie sex-specific differences in disease susceptibility in humans. Despite its importance, we have little direct information about where sexually antagonistic selection acts in the genome or about its role in creating differences between the sexes. Sex chromosomes are the most promising context in which to study sexually antagonistic selection because they are predicted to be hotspots for the accumulation of genes experiencing this type of selection. Furthermore, sexually antagonistic selection is thought to be responsible for the evolution of the distinctive properties of sex chromosomes, such as a reduction in recombination between the X and the Y, and the subsequent degeneration of the Y. Much of the existing data from sex chromosomes, however, comes from systems with sex chromosomes that are highly degenerate and gene-poor, rendering the identification of genes experiencing sexually antagonistic selection difficult or impossible. Stickleback fishes are an emerging model system whose sex chromosomes still recombine and are gene-rich, making them ideally suited for studying sexually antagonistic selection. This research project will exploit those properties to learn how sexually antagonistic selection sculpts chromosomes, genes, and phenotypes. The three major aims will: (1) use genetic, cytogenetic, and genomic tools to reveal how recombination between the X and Y chromosomes becomes suppressed; (2) obtain whole genome sequences to study how the many differences between males and females alter the evolutionary trajectories of genes and chromosomes; and (3) use new statistical methods to identify the genetic and phenotypic targets of sexually antagonistic selection. The results from this project will be useful in context far beyond sex chromosomes in sticklebacks. It will generate technical innovations, such as new statistical methods for analyzing DNA variation that will be valuable for studies of chromosomal rearrangements on autosomes in diverse taxa. Furthermore, insights from this work will provide perspectives on the potential for selection to establish genes that are detrimental to health in al species, including humans.