Understanding Male Gamete Competition Using Unique Molecular Tags

由于精子体积小，以及观察复杂的雌性生殖道内发生的事件所面临的技术挑战，包括人类在内的内部受精物种对生殖的许多基本方面仍然知之甚少。本项目是一个详细的调查遗传，生理和行为方面的事件发生在一个模型系统：果蝇黑腹果蝇和密切相关的物种。这是第一次使用独特的转基因蝇株产生的精子，其头部表达绿色（GFP）或红色荧光蛋白（RFP），可以直接实时观察这些事件。实验将探讨精子迁移、精子储存、卵子受精的机制，来自不同雄性的精子竞争使两次交配的雌性卵子受精的机制，以及在近亲物种之间的杂交交配中导致生殖失败的射精-雌性不相容机制。拟议的研究有可能在生殖生理学和遗传学、性选择和物种形成等领域产生分水岭式的进展。我们对精子在女性体内行为的理解以及对导致精子-雌性不相容的候选基因的识别所取得的进展，进一步可能导致我们对人类不孕症的理解和治疗的进步。

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.