The genetics of postmating isolation mechanisms between species of Drosophila

繁殖在生物学中起着关键作用，了解基因变化如何阻碍杂交并允许不同物种的进化是进化的核心问题。确定基因和表型之间的联系，例如限制个体群体之间基因流动的联系，对于理解物种形成过程和生物多样性的机械起源至关重要。在密切相关的物种中，生殖性状的差异往往比其他性状的差异更明显，这些差异影响物种间杂交的潜力（即物种相容性）。物种的相容性并不随着交配过程本身而结束。事实上，雄性与雄性之间的竞争和雌性的选择在交配后很长一段时间内都会继续影响兼容性。我的工作旨在了解生殖不相容的遗传基础，特别是交配后合子后异常，使杂交雄性不育和交配后前合子的挑战，影响精子竞争。在我的研究的下一阶段，我的目标是：1）测试先前鉴定的基因和基因类的作用（例如蛋白酶），2）鉴定有助于物种之间HMS的基因相互作用和途径，3）有助于我们理解导致物种之间隔离的不相容性的机制基础和表型表达，4）确定物种间精子竞争和交配后前合子隔离的共同遗传基础，5）理解雄性生殖基因的一般进化模式，特别是与交配后生殖隔离相关的基因，从编码到非编码调控进化。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繁殖成功率变化相关的候选基因。该提案的创新之处在于将这些方法在基因组水平上与严格的表型描述和基因操作技术相结合，以确定有助于杂种雄性不育和精子竞争力的特定基因。最终，这些结果将进一步加深我们对物种分化和这种过程背后的遗传基础的认识。测试HMS中基因表达变化的作用将对我们理解基因调控和表型表现之间的联系具有创新性和变革性。另一个创新的方面将是确定基因的相互作用和途径，而不是单一的基因有助于HMS和测试，是否基于共同的遗传机制，性选择（精子竞争）可以导致或有助于物种形成（交配后前合子隔离）。

Reproduction plays a pivotal role in biology and understanding how gene changes can impede interbreeding and allow for the evolution of different species is a central problem in evolution. Identifying links between genes and phenotypes, such as those that restrict gene flow between groups of individuals, is critical for understanding the process of speciation and the mechanistic origin of biodiversity. Among closely related species, differences in reproductive traits tend to be more pronounced than differences in other traits, and these differences affect the potential of species to interbreed (i.e. species compatibility). Species compatibility does not end with the mating process itself. Indeed male-male competition and female choice continue to influence compatibility long after mating. My work aims to understand the genetic basis of reproductive incompatibilities, specifically postmating postzygotic anomalies that render hybrid males sterile and postcopulatory prezygotic challenges that affect sperm competition. During the next phase of my research I aim to: 1) Test the role of previously identified genes and gene classes (e.g. proteases) in hybrid male sterility (HMS), 2) identify gene interactions and pathways contributing to HMS between species, 3) contribute towards our understanding of the mechanistic basis and phenotypic expression of incompatibilities that cause isolation between species, 4) identify common genetic basis to sperm competition and postmating prezygotic isolation between species, and 5) understand patterns of evolution of male reproductive genes in general and those linked to postmating reproductive isolation in particular, with an interest moving from coding to noncoding regulatory evolution. 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. The innovation of this proposal is to combine these approaches at the genome level, with rigorous phenotypic descriptions and gene manipulation technologies to identify specific genes contributing to hybrid male sterility and sperm competitiveness. Ultimately, results will further our knowledge on species differentiation and the genetic basis underlying such process. Testing the role of changes in gene expression in HMS will be innovative and transformative towards our understanding of links between gene regulation and phenotypic manifestation. Another innovative aspect will be identifying gene interactions and pathways rather than single genes contributing to HMS and testing whether, based on common genetic mechanisms, sexual selection (sperm competition) can cause or contribute to speciation (postmating prezygotic isolation).