INDUCTION OF LEG-SHAKING, KNOCK-DOWN AND KILLING RESPONSES BY GAMMA-RAY IRRADIATION IN SHAKER MUTANTS OF DROSOPHILA-MELANOGASTER

Induction of membrane-associated responses, a leg-shaking, a knock-dow n and a killing, by gamma-ray irradiation was investigated in Shaker ( Sh) mutants of Drosophila melanogaster in which the gene cords for the A-current K-dagger channel. Sh mutants were more sensitive in the kno ck-down response after gamma-ray irradiation than wild types. There we re a great amount of sex difference in the knock-down response, males being more sensitive than females, but not in the killing response. Th e sex difference was larger than gene dosage effect on X chromosome in females. Genetical analysis revealed that the sensitivity of the knoc k-down response is an incompletely dominant character without maternal effects. The leg-shaking response, which had previously been reported to be induced by ether treatment, was demonstrated in the head-remove d flies of Sh mutants. It was found to be the most sensitive among the responses tested, and may involve changes in K-dagger channel. The kn ock-down response may be related to expansion of the leg-shaking respo nse. The killing response should have causes different from the leg-sh aking and the knock-down responses judging from the lack of correlatio n with them.