性别决定是生物学的基本问题之一。转录因子Foxl2在雌性性别决定中发挥重要作用，但涉及的分子机制还有待进一步研究。与哺乳类不同，鱼类存在两个Foxl2，即Foxl2a和Foxl2b，有趣的是Foxl2a表达于体细胞，而Foxl2b表达于生殖细胞。近年我们已经通过基因敲除和过表达首次证明了Foxl2a在雌性性别决定中的重要性。基于前期研究结果，我们推测Foxl2a调控的体细胞性别决定信号通路与Foxl2b调控的生殖细胞性别决定信号通路都作用于鱼类雌性性别决定，两者缺一不可。本项目拟采用一系列离体和在体研究手段深入分析Foxl2a调控的雌性性别决定通路基因；分析Foxl2b在雌性性别决定中的功能及分子机制；最后解析Foxl2a和Foxl2b调控体细胞和生殖细胞互作的分子机制。本项目有助于阐明鱼类雌性性别决定的分子机制，为水产养殖鱼类的性别控制和遗传育种提供理论基础。

Sex determination is one of the fundamental aspects of biology. The transcription factor Foxl2 plays a decisive role in vertebrate sex determination, however, the molecular mechanism involved in this process is still to be deeply elucidated. Different from mammals, two Foxl2s(two copies of Foxl2), Foxl2a and Foxl2b, have been identified in most fishes. It is interesting that Foxl2a was expressed in gonadal somatic cells, while Foxl2b expressed in germ cells. Based on previous results, we hypothesize that both of Foxl2a in somatic cells and Foxl2b in germ cells take part in fish female sex determination. This project will adopt a series of in vitro and in vivo technologies to isolate the genes regulated by Foxl2a in sex determination signal pathway. In vivo gene knockout (loss of function in XX) and overexpression (gain of function in XY) experiments will be carried out to figure out the functions of Foxl2b signaling pathway in female sex determination. Finally, the crosstalk between Somatic cells and germ cells will be investigated. Taken together, the aim of this project was to clarify the molecular mechanism of female fish sex determination. The implementation of this proposal will provide a theoretical basis for the sex control and genetic breeding of fish in aquaculture.