mutation increases the number of COSA-1 foci in and mutants.

Crossover designation factors such as COSA-1 are concentrated at the specific DNA double-strand break (DSB) sites to promote crossover formation. mutants, which show defects in the homologous chromosome pairing of chromosomes II and III, increase the COSA-1 foci/normal bivalent state compared to the expected value. The excess designation was suppressed by an additional mutation in in mutants. We demonstrated that the number of COSA-1 foci in and mutants, showing defects in the pairing of the X and V chromosomes, respectively, increased compared to the expected value, and mutation accelerated the number of COSA-1 foci in oogenesis.