Evolution of Nematode Sex Determination

性别决定机制在不同的门之间差异很大，甚至在它们深层次同源性的证据积累时也是如此。这个项目使用线虫属线虫来研究性别决定是如何在短时间尺度上进化的。它提供了一个具有良好特征的参考物种(线虫)、性模式的变异(雄雄异体与生殖器)，以及第一对密切相关的动物基因组序列。该项目将开发布里奇萨线虫作为一个真正的遗传系统，这将使人们能够与线虫进行精确的比较。我们使用了两种互补的方法来鉴定布里吉萨锥虫性别决定突变：基于表型的经典正向遗传筛查和通过基于聚合酶链式反应的方法对缺失突变的反向遗传筛查。这些方法将有助于阐明交配系统是如何进化的，以及在两个收敛的两性物种中，生殖系发育的细节是相同的还是不同的。此外，该项目还将有助于发展成一个成熟的发育遗传系统。本科生和研究生的参与是该项目的核心，确保对年轻科学家的培训和指导是一个主要组成部分。

ABSTRACTSex determination mechanisms vary wildly from phylum to phylum, even as evidence for their deep homology accumulates. This project uses the nematode genus Caenorhabditis to study how sex determination evolves over short time scales. It offers a well-characterized reference species (C. elegans), variation in sexual mode (androdioecy vs. gonochorism), and the first pair of closely related animal genome sequences. The project will develop C. briggsae as a true genetic system, which will enable precise comparisons with C. elegans. Two complementary approaches for identifying C. briggsae sex determination mutations are used: classical forward genetic screens based on phenotype and reverse genetic screens for deletion mutations via a PCR-based method. Together these approaches will help clarify how mating systems evolve, and whether the details of germline development are the same or different in two convergent hermaphroditic species. In addition, the project will contribute to the development of C. briggsae as a mature developmental genetic system. Undergraduate and graduate student participation is central to the project, ensuring that the training and mentoring of young scientists is a major component.