Transmission of male recombination,segregation distortion and sex-ratio imbalance inDrosophila melanogaster

From the first test cross progenies of control (no larval transfers; no ethyl methanesulphonate), physical stress (two larval transfers; no ethyl methanesulphonate) and 0.75% ethyl methanesulphonate (two larval transfers; 0.75% ethyl methanesulphonate)-treated F₁ (Oregon K +/dumpy black cinnabar, dp b cn) males ofDrosophila melanogaster, respectively, 6,10 and 52 wild-looking first test cross males were again test crossed to obtain second generation. The overall percentages of male recombination detected in the second test cross progenies, in the three sets of experiments, were statistically the same as those in the first test cross progenies. Thus the enhanced male recombination caused by physical stress (with or without ethyl methanesulphonate) was transmitted to next generation. Non-reciprocal male recombination was observed indp b but not inb cn region in both first and second test cross progenies. Three abnormalities, (i) production of wild-type flies in majority overdp b cn type, (ii) Non-Mendelian segregation atdp b andcn loci and (iii) sex-ratio differences fordp bcn and +b cn types observed in test cross progenies of F₁ males ofDrosophila melanogaster were transmitted to next generation when induced with 0.75 % ethyl methanesulphonate but not when these abnormalities were induced with physical stress. The data suggest possible association of non-reciprocal male recombination, segregation distortion and sex-ratio imbalance inDrosophila melanogaster. In fact these may be representing different aspects of the same phenomenon