Understanding Male Gamete Competition Using Unique Molecular Tags

Syracuse University, Syracuse NY

Investigators

Abstract

Because of the small size of sperm and the technical challenges of observing events taking place inside the complex reproductive tract of females, there are numerous, fundamental aspects of reproduction that remain poorly understood in internally fertilizing species, including humans. This project is a detailed investigation of genetic, physiological and behavioral aspects of events taking place between insemination and fertilization in a model system: the fruit fly Drosophila melanogaster and closely related species. For the first time, these events will be directly observed in real time using unique transgenic fly strains producing sperm with heads that express green (GFP) or red fluorescent protein (RFP). Experiments will explore mechanisms of sperm migration, sperm storage, egg fertilization, the mechanisms by which sperm from different males compete to fertilize the eggs of twice-mated females, and mechanisms of ejaculate-female incompatibility contributing to reproductive failure in hybrid matings between closely related species. The proposed research has the potential to generate watershed advances in the fields of reproductive physiology and genetics, sexual selection and speciation. Resulting progress in our understanding of sperm behavior within females and the identification of candidate genes contributing to sperm-female incompatibility are further likely to lead to advances in our understanding and treatment of human infertility.