In mature oocytes derived from F1 Unc animals that were heterozygous for the
Ce-spo-11 mutation, depletion of
Ce-rdh-1/rad-51 by RNAi was associated with the presence of aberrant chromosomes. In contrast, in mature oocytes derived from F1 animals (not Unc) that were homozygous for the
Ce-spo-11 mutation and depleted for
Ce-rdh-1/rad-51, twelve univalents were observed, which is the
Ce-spo-11 mutant phenotype. These results indicate that the
Ce-rdh-1/rad-51 RNAi effect is suppressed in the
Ce-spo-11 mutant background. However, the twelve univalents in both defects of
Ce-rdh-1/rad-51 and
Ce-spo-11 could no longer be rescued by X-ray irradiation. Thus, the
Ce-spo-11 mutation is epistatic to the
Ce-rdh-1/rad-51 depletion, which interferes with homologous recombination after the generation of DSBs by both endogenous
Ce-spo-11 and exogenous DNA lesion during meiosis.