Molecular mechanism of meiotic control : Studies byusing hybrid-sterile organisms.

由于同源染色体配对和重组的减数分裂失败，大多数杂交动物雌雄不育。然而，牦牛和牛的杂交品种只有雄性不育。男性和女性的染色体，可能还有基因，除了性染色体外，显然是相同的。因此，我们推测性别生育能力的差异将来自生殖细胞的过程。我们的研究表明：(1)在不育的睾丸中，粗线的减数分裂降解是明显的。(2)用western法和原位FISH法研究了减数分裂特异性基因LIM 9、10、13、15、18在这些降解的减数分裂细胞中也有表达。(3)光学和电子显微镜检查显示，除少数节段外，存在正常的突触体复合体。这些结果表明，减数分裂通常持续到粗线的后一半，但随后可能会诱导染色体DNA的断裂，就像在x常染色体易位雄性小鼠中观察到的那样。有趣的是，随着雄性不育的代代恢复，雌性的F1、F2、F3和F4（正常生育能力）与睾丸中存在的正常减数分裂细胞的百分比和睾丸的大小相似。雄性特异性减数分裂失败的分子机制仍有待研究。本研究为蒙古育种研究和减数分裂基础研究做出了贡献。

Most of hybrid animals are sterile in both male and female due to the meiotic failure in pairing of homologous chromosomes and the recombination. However, the hyburid between yak and cattle shows only male-sterile. The chromosomes, probably the genes also, in both male and female are apparently identical except the sex chromosomes. Thus, we have speculated that the difference in fertility in sex will come from the process for germ cells. Our study indicated (1) in sterile testes, meiotic degradation at pachytene was evident. (2) expression of meiosis specific genes, LIM 9,10,13,15,18, occured even in these degrading meiotic cells, studied by both westem method and in situ FISH method using the antibodies raised against the proteins prepared in E.coli. (3) Optical and electron microscopic studies indicated the presence of normal synaptonema complex except a few segmentations. These results indicate that meiosis proceeds until later half of pachytene normally but then fragmentation of chromosomal DNA,like ones observed in X-autosomal translocation male mice, may be induced. It is interesting to find that as male-sterility recovered by generations, F1, F2, F3 and F4 (noraml fertility) through females, parallels with the percent of normal meiotic cells present in testes and the size of the testes. The molecular mechanisms for male specific failure of meiosis remains to be studied. Nevertheles, this study made a contribution to mongolian breeding research and the basic research for meiosis.