The Genomic Basis and Molecular Mechanisms of Speciation

项目摘要 进化生物学中的一个基本问题是理解进化的分子遗传基础。 物种形成物种形成研究的最新进展提高了我们对种间差异的理解， 但我们仍然缺乏对早期物种之间分化的分子过程的全面了解。 在少数情况下，生殖隔离的遗传机制已经阐明，这些 总是解决晚期进化和/或混合功能障碍。这意味着我们还缺乏一个普遍的认识 控制合子前生殖障碍的分子过程，尽管这些过程通常很重要， 在物种形成的早期 我的实验室将通过识别前合子和后合子再形成的分子遗传基础来解决这个问题。 果蝇种亚组成员之间的生产隔离。该物种提供 一个特别独特的机会，解剖前合子障碍的遗传和分子机制， 这个群体的成员倾向于在物种之间甚至在物种之间迅速进化出这些类型的障碍。 同一物种的种群。我们的总体方法集成了几种策略，以回答以下问题 问题：造成物种间生殖隔离的遗传机制是什么？哪个分子- 这些遗传机制的分歧会影响细胞和细胞的过程？什么是进化 驱使物种间相关基因分化的力量？什么是自然遗传景观 物种内部和物种之间的变异促进了这些基因的进化分化？ 本提案中的第一个项目将侧重于交配后合子前障碍（即，配子不亲和 ities）。我以前已经证明配子不相容在D.男性化亚组， 遗传基础是适度复杂的，但使用分子遗传学技术的组合是高度易处理的 再加上繁殖性状的转录组学和蛋白质组学分析。第二个项目将解决 由Y和X染色体之间的不相容性引起的杂种雄性不育的机制。 果蝇Y染色体携带几种雄性生育因子，但它很少直接参与 近缘物种间的种间杂种不育。我们的初步数据显示Y染色体 是导致杂种不育的必要条件和充分条件。 这项提案中的研究将是创新的，因为我们将以创造性的方式部署尖端工具， 将使我们能够在新建立的模型系统中剖析复杂的遗传机制。

PROJECT SUMMARY One of the fundamental problems in evolutionary biology is to understand the molecular genetic basis of speciation. Recent advances in speciation research have improved our understanding of interspecific divergence, but we still lack a comprehensive understanding of the molecular processes that diverge among incipient species. In the handful of cases where the genetic mechanisms of reproductive isolation have been elucidated, these invariably tackle late-evolving and/or hybrid dysfunction. This means that we still lack a general understanding of the molecular processes that govern pre-zygotic reproductive barriers, even though these are often important early in the speciation process. My lab will tackle this problem by identifying the molecular genetic basis of pre-zygotic and post-zygotic re- productive isolation between members of the Drosophila virilis species sub-group. This species group provides an especially unique opportunity to dissect the genetic and molecular mechanisms of pre-zygotic barriers, as members of this group are prone to evolve these types of barriers quickly between species and even among populations of the same species. Our overall approach integrates several strategies to answer the following questions: What are the genetic mechanisms that cause reproductive isolation between species? Which molec- ular and cellular processes are affected by divergence of these genetic mechanisms? What are the evolutionary forces that drive divergence of the relevant genes between species? What is the landscape of natural genetic variation within and between species that facilitates evolutionary divergence of these genes? The first project within this proposal will focus on post-mating pre-zygotic barriers (i.e., gametic incompatibil- ities). I have previously shown that gametic incompatibilities are rampant in the D. virilis sub-group, and that the genetic basis is moderately complex but highly tractable using a combination of molecular genetics techniques coupled with transcriptomic and proteomic analyses of reproductive traits. The second project will tackle the mechanisms of hybrid male sterility that are caused by incompatibilities between the Y and X chromosomes. The Drosophila Y chromosome carries several male fertility factors, but it has seldom been directly implicated in interspecific hybrid sterility between closely related species. Our preliminary data show that the Y chromosome is necessary and sufficient to cause sterility in hybrids. The research in this proposal will be innovative because we will deploy cutting edge tools in creative ways that will allow us to dissect complex genetic mechanisms in a newly established model system.