The Genomic Basis and Molecular Mechanisms of Speciation

项目总结 进化生物学中的一个基本问题是理解基因突变的分子遗传学基础。 物种形成。物种形成研究的最新进展提高了我们对种间fic分歧的理解， 但我们仍然缺乏对初始物种之间分歧的分子过程的全面了解。 在少数生殖隔离的遗传机制已被阐明的情况下，这些 一成不变地解决晚期进化和/或混合性功能障碍。这意味着我们仍然缺乏普遍的认识。 控制合子前生殖障碍的分子过程，尽管这些通常是重要的 在物种形成过程的早期。 我的实验室将通过鉴定合子前和合子后的分子遗传学基础来解决这个问题。 果蝇种亚群成员之间的生产性隔离。这个物种组织提供了 一个特别难得的机会来剖析合子前障碍的遗传和分子机制，如 这一群体的成员容易在物种之间，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个策略来回答以下问题 问题：造成物种间生殖隔离的遗传机制是什么？哪一种分子- 这些遗传机制的不同会影响叶和细胞的过程吗？什么是进化？ 推动物种间相关基因分化的力量是什么？自然遗传的景观是什么？ 物种内和物种间的变异促进了这些基因的进化分化吗？ 这项提案中的fiRST项目将专注于交配前合子障碍(即配子不相容-- 城市)。我以前已经证明，配子不相容在D.virilis亚群中非常猖獗，而且 使用分子遗传学技术的组合，遗传基础是中等复杂的，但非常容易处理 再加上对生殖特征的转录和蛋白质组学分析。第二个项目将解决 Y染色体和X染色体之间的不亲和性导致的杂交雄性不育机制。 果蝇Y染色体携带几个男性生育因子，但很少被直接牵连到 种间fic近缘种间杂种不育。我们的初步数据显示，Y染色体 fi是造成杂种不育的必要条件和充分条件。 这项计划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.