粗线期检验点在雌核发育二倍体鲫鲤不减数卵子形成中的作用机制

粗线期检验点(Pachytene Checkpoint)是减数分裂过程中特有的细胞周期调控机制，通过调节和监控同源染色体的重组和联会，保证重组和联会高度有序地完成，以确保遗传物质的准确传递。正常条件下异源二倍体在减数分裂中非同源染色体不能正常重组和联会，在粗线期检验点的作用下减数分裂过程停滞，生殖细胞凋亡从而导致性腺不育。然而，雌核发育二倍体鲫鲤作为一种异源二倍体鱼却能稳定产生二倍体卵子，在这种不减数卵子的形成过程中粗线期检验点如何发挥其作用值得深入研究。本项目将对雌核发育二倍体鲫鲤不减数卵子形成过程中的DNA双链断裂、粗线期检验点的激活、检验点启动遗传物质加倍、同源染色体重组联会等关键事件的分子机制进行研究，以阐明粗线期检验点在异源二倍体生殖发育中的调控通路，揭示不减数配子的形成机制，本项目的研究不仅在繁殖生物学中具有重要意义，而且在生产应用中有助于指导鱼类杂交育种和多倍体鱼的培育。

The pachytene checkpoint is a unique regulation mechanism of cell cycle during meiosis. By regulating and monitoring the recombination and synapsis of homologous chromosomes, pachytene checkpoint orders the recombination and synapsis completed in a right way to ensure the accurate transmission of genetic material. Normally, allodiploid is infertile under the action of pachytene checkpoint, because chromosomes cannot complete the recombination and synapsis. However, a gynogenetic diploid hybrid fish as an allodiploid can stably produce diploid eggs. This project intends to investigate the effect of pachytene checkpoint in the formation of diploid egg. It will take the study of molecular mechanisms of DNA double strand break, pachytene checkpoint activation, doubling of genetic material, recombination and synapsis of homologous chromosomes to elucidate the regulatory pathway of pachytene checkpoint in the allodiploids and reveal the formation mechanism of unreduced gametes. This project not only has important significance in reproductive biology, but also helps to guide the fish breeding and produce polyploid fish.