Estimation of the levels of radiation-induced P-element transposition in Drosophila melanogaster experimental populations and laboratory strains

When experimental P + M populations were exposed to chronic gamma-irradiation (0.31 mGy/h), the highest instability level of the singed-weak (sn (w) ) locus was observed in F-3-F-10 with a subsequent decrease and stabilization of the mutation rate. The sn (w) mutation rate was within the range of spontaneous variation in conditions of P-M hybrid dysgenesis and irradiation of males of the Harwich laboratory strain with active P elements at 1.61 mGy/h. The instability of the sn (w) locus was significantly higher at lower dose rates (0.23 and 0.31 mGy/h), suggesting a nonlinear dose-effect relationship.