Sexual selection and molecular evolution of postmating reproductive incompatibilities

生殖在进化生物学中起着核心作用，因为生殖活动的中断，从交配到配子竞争受精的能力，都会降低适应性。在相关物种中，生殖特征的差异比其他特征的差异更明显，这种差异可以影响物种的兼容性，并有助于物种形成。我的工作集中在两个影响交配后繁殖成功的现象：同种精子优先(CSP)和不育杂交种的配子发育中断。我也有兴趣了解性选择在与交配后成功相关的基因上所起的作用。在我下一阶段的研究中，我的目标是：1)识别和功能测试候选CSP基因，2)辨别性别选择和由其他因素驱动的快速分化，例如CSP验证基因和其他与交配后生殖适合性相关的基因的松弛选择限制或突变偏见，3)评估调控序列中的遗传分歧在种间雄性杂种精子发生基因下调中的作用。在我的实验室里，我们成功地结合了经典遗传学、基因组学和分子进化方法来识别与生殖成功变异相关的候选基因，特别是与CSP相关的基因和影响精子发生的基因变体。在这项研究中，我通过使用SNP-表型关联和基因敲除来测试这些候选基因的功能意义，从而为基因验证提供了明确的证据。与生殖成功和受精有关的基因将被用来测试性选择如何塑造它们的进化。这些结果将有助于我们在生殖基因进化过程中在分子水平上了解物种分化和性别选择的影响。已识别的基因将成为比较基因组搜索的直接目标，并识别与进化过渡有关的保守和分歧。

Reproduction has a central role in evolutionary biology because disruptions in reproductive activities, from mating to gamete ability to compete for fertilization, reduce fitness. Among related species, differences in reproductive traits are more pronounced than differences in other traits and such differences can affect species compatibility and contribute to speciation. My work focuses on two phenomena that influence reproductive success after copulation; conspecific sperm precedence (CSP) and gamete development disruption in sterile hybrids. I am also interested in understanding the role of sexual selection on genes linked to postcopulatory success. During the next phase of my research I aim to: 1) identify and functionally test candidate CSP genes, 2) discern between sexual selection and rapid divergence driven by other factors, such as relaxed selective constraints or mutational bias at CSP validated genes and other genes linked to postcopulatory reproductive fitness, 3) evaluate the role of genetic divergence in regulatory sequences in the down regulation of spermatogenesis genes in interspecies male hybrids. In my lab, we have successfully used a combination of classical genetics, genomics and molecular evolution approaches to identify candidate genes associated with variation in reproductive success, particularly genes involved in CSP and gene variants affecting spermatogenesis. In this grant, I expand upon this research by testing the functional significance of these candidate genes using SNP-phenotype associations and genetic knockdowns, thus providing definitive evidence for gene validation. Genes linked to reproductive success and fertilization will be used to test how sexual selection molded their evolution. These results will contribute to our knowledge of species differentiation and the impact of sexual selection at the molecular level during the evolution of reproductive genes. Identified genes will become immediate targets for comparative genomic searches and the identification of conservation and divergence linked to evolutionary transitions.