Gradual decline of formaldehyde-induced male recombination in successive generations of Drosophila melanogaster.

Transmission of formaldehyde (FA)-induced male recombination was studied in D. melanogaster for three generations. Among recombinants, al dp was the most and b pr the next most frequent phenotype in the progenies of F1, TC1, TC2 and TC3 males of genotype + /al dp br. Non-reciprocal male recombination for dp-b and b-pr regions whereas reciprocal male recombination for al-dp region were noted. Percentages of recombinants observed in TC1 (1.052), TC2 (0.876), TC3 (0.698) and TC4 (0.497) progenies of D. melanogaster males were not statistically different from each other in any two successive generations. A continuous but gradual decline in the frequency of FA-induced male recombination was observed in the three subsequent generations studied.