DISSERTATION RESEARCH: Effects of Mating System on Accessory Gland Protein Evolution in Heliconius Butterflies

在有性繁殖的动物中，直接参与受精的蛋白质在近亲物种之间的比较中往往存在不同寻常的差异。在从软体动物到哺乳动物的各种生物中观察到的快速分化的原因，目前还没有得到很好的理解。这个项目批判性地检验了一种假设，即快速的遗传变化是雄性之间为使雌性受精的机会而竞争的结果。本研究以蝴蝶（一种具有悠久遗传研究历史的昆虫）为研究对象，主要有两个目标：1)确定与受精和产卵有关的蛋白质编码基因；2)比较不同交配系统（即不同雄蝶竞争水平）物种之间这些基因的差异模式。如果交配系统影响分子变化的速率，那么生殖蛋白之间的遗传分化水平应该与交配系统相关。了解调解精子和卵子之间相互作用的蛋白质变化的性质和原因，将为了解多样性的起源（新物种是如何产生的）提供重要的见解。此外，研究物种之间不寻常的遗传差异模式也将提供对生物功能的重要见解，对医学、农业和环境都有影响。最终，确定在生殖蛋白中发现的不寻常差异的原因将有助于控制害虫和治疗不孕症。

Proteins that are directly involved in fertilization in sexually reproducing animals are often unusually divergent when compared between closely related species. The reasons for rapid divergence, which has been observed in organisms ranging from mollusks to mammals, are currently not well understood. This project critically examines the hypothesis that rapid genetic change is a consequence of competition among males for opportunities to fertilize females. The proposed research focuses on Heliconius butterflies (a group of insects with a long history in genetic research) and has two major goals: 1) to identify genes encoding proteins involved in fertilization and egg laying and 2) to compare patterns of divergence in these genes between species with different mating systems, i.e., different levels of competition among males. If mating system influences rates of molecular change, levels of genetic divergence among reproductive proteins should correlate with mating system. Understanding the nature and causes of changes in proteins that mediate interactions between sperm and egg will provide important insights into the origin of diversity (how new species arise). In addition, examining unusual patterns of genetic divergence between species will also offer important insights into biological function, with implications for medicine, agriculture, and the environment. Ultimately, determining the cause of the unusual divergence found among reproductive proteins will help to inform efforts to control insect pests and treat infertility.