The effects of recombination-defective meiotic mutants in Drosophila melanogaster on gonial recombination in males.

Recombination-defective female meiotic mutants representing 7 loci in Drosophila melanogaster have been examined for effects on gonial recombination in males. These loci were chosen for study because they represent a broad range of the known types of defects in processes necessary for meiotic recombination and somatic chromosome stability. Alleles at 6 of the loci studied did not increase the frequency of gonial recombination in males, whereas a mutant at one locus was associated with an increase (about 10-fold) in gonial recombination. These results suggest that the defects in chromosomal metabolism caused by these recombination, and in some cases repair, defective mutants are distinct from those of the male-recombination promoting elements (Mr) recently isolated from many natural populations. Analysis of the spontaneous events detected in this study showed that a third to a half of the events detected are actually of mutational rather than recombinational origin.