Sexual selection and molecular evolution of postmating reproductive incompatibilities

生殖在进化生物学中起着核心作用，因为从交配到配子竞争授精的能力，生殖活动的中断会降低适应性。在亲缘物种中，生殖性状的差异比其他性状的差异更为明显，这种差异可以影响物种的相容性，并有助于物种的形成。我的工作重点是影响交配后繁殖成功的两个现象；不育杂交种的同种精子优先（CSP）和配子发育破坏。我也对理解性选择在与交配后成功相关的基因中的作用感兴趣。在下一阶段的研究中，我的目标是：1)鉴定和功能测试候选CSP基因；2)辨别性选择与其他因素驱动的快速分化之间的关系，如CSP验证基因和其他与交配后生殖适应性相关的基因的放松选择约束或突变偏倚；3)评估遗传分化调控序列在种间雄性杂交种中精子发生基因下调中的作用。在我的实验室里，我们已经成功地结合了经典遗传学、基因组学和分子进化方法，确定了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异。在这项资助中，我通过使用snp表型关联和基因敲低测试这些候选基因的功能意义来扩展这项研究，从而为基因验证提供明确的证据。与繁殖成功和受精有关的基因将被用来测试性选择如何影响它们的进化。这些结果将有助于我们在分子水平上了解生殖基因进化过程中物种分化和性选择的影响。已鉴定的基因将成为比较基因组搜索和鉴定与进化过渡有关的保存和分化的直接目标。

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.