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.
