[Expression levels of Cdc2 and Cdc25A mRNA in cattle, yak, and cattle-yak testis].

The infertility of cattle-yak, which is the hybrid offspring of cattle and yak, is a difficult problem in crossbreeding and improvement of yak. Cdc2 and Cdc25A are the key genes of meiosis. The decline of their expression levels will cause the spermatogenesis failure and lead to infertility.