DISSERTATION RESEARCH: Consequences of sympatry and allopatry for variation in reproductive genes of Drosophila pseudoobscura

许多因素影响着植物和动物的配偶选择，包括选择一个能提供最优质后代的配偶，同时避免与不同物种的个体交配。将这些因素整合到一个单一的选择中，意味着物种内配偶选择所涉及的特征可能是导致物种彼此分化的相同特征。最近，研究人员利用转基因的黑腹果蝇表明，控制物种内配偶选择的基因也参与物种歧视。这个项目正在自然系统中测试这种联系，以了解不同种群如何积累控制配偶选择和物种歧视的基因变化。这些数据将为了解配偶选择自然变化和生殖隔离种群形成的分子机制提供洞见，这是理解新物种如何在进化过程中产生的重要因素。本研究将利用高深度核苷酸测序技术，检测果蝇（Drosophila pseudobscura）自然种群中生殖基因的DNA序列和基因表达变异。该实验对比了发生在种群中与密切相关的物种共同发生的基因变化，因此在选择配偶时必须歧视它们，以及没有接触到其他物种的种群的变化。分析将评估所有生殖基因的遗传变异，特别是已知影响配子竞争的基因。这些变异将与物种内和物种间交配选择的表型数据相关联，以区分对交配选择、物种歧视和生殖行为都很重要的基因。

Many factors influence mate choice in both plants and animals, including choosing a mate that will provide the best quality offspring while avoiding individuals of different species. The integration of these factors into a single choice implies that traits involved in mate selection within species could be the same traits that cause species to diverge from one another. Recently, the investigators used genetically modified Drosophila melanogaster to show that the same genes that control within species mate choice are also involved in species discrimination. This project is testing this association in a natural system, to understand how different populations accumulate changes in genes that control mate choice and species discrimination. These data will provide insight into the molecular mechanisms underlying natural variation in mate choice and the formation of reproductively isolated populations, which are important factors in understanding how new species arise over evolutionary time. The proposed research will examine DNA sequence and gene expression variation in reproductive genes in natural populations of the fruit fly Drosophila pseudoobscura, using high depth nucleotide sequencing. The experiment contrasts genetic changes that have occurred in populations that co-occur with closely related species, and thus must discriminate against them during mate choice, with changes in populations that are not exposed to other species. Analyses will assess genetic variation across all reproductive genes, as well as specifically in genes known to affect gamete competition. These variants will be associated with phenotypic data on mate choice within and between species, to differentiate genes that are important to mate choice, to species discrimination, and to both reproductive behaviors.