Studies on a recombination-deficient mutant of drosophila II. Response to X-rays and alkylating agents

Abstract

When mature sperm of the recombination-deficient mutant c3 G of Drosophila me melanogaster are treated with X-rays or the alkylating agents ethyl methanesulphonate and diepoxybutane, highly significant differences are found in the frequencies of recessive sex-linked lethals and translocations in the case of X-rays, and in lethals only in the case of alkylating agents. It is shown that this difference occurs in the response of mutant and wild-type sperm treated in the heterozygous male, eliminating any possibility that background genetic differences in the mutant and wild-type strains were responsible for the results. It is suggested that an initial stage in the repair process is reduced or missing in the mutant and that the results further evidence of a connection between recombination and repair in higher organisms. The chemical results also suggest that the formation of point mutations and chromosome aberrations arise from different events as the latter do not differ in frequency in the mutant although the lethals do so considerably.