[Mitotic recombination in cleavage divisions of Drosophila melanogaster. V. Effect of ethylmethane sulfonate on female parents].

The data obtained show that after ethylmethanesulfonate treatment of Drosophila females and their crossing with untreated males the mitotic recombinants can be found among F1 offsprings. The recombination took place in cleavage division nuclei between treated female and intact male X-chromosomes. The rates of recombinations were lower than those caused by treatment of males with the same doses of EMS. The patterns of recombination were similar in both cases. Most of the recombinants were mosaic females. The results of present study as well as data obtained in previous experiments suggest that distribution of breaks along X-chromosome depends on sex of the treated gametes and does not depend on the mutagen used. In heterozygotes carrying treated mother's X-chromosome the recombination usually occurs in the proximal part of X-chromosome while the treatment of male parents frequently causes the recombination in the distal region of X-chromosomes of their daughters.