Keywords: radioadaptation, chronic irradiation, lifespan, Drosophila, gamma irradiation, isogenic strains, low radiation, heterogenic strains
Chronic gamma-irradiation effect on Drosophila melanogaster lifespan in generations of wild-type isogenic and heterogenic strains
The dynamics of lifespan in 14 successive generations after chronic ͏-irradiation in heterogenic (Canton-S) and isogenic (Oregon-R spa) Drosophila wild-type strains were investigated. The γ-source was 226Ra at a dose rate of 60 cGy per generation. After chronic irradiation in the heterogenic line Canton-S, the cyclic lifespan oscillations disappeared after the fifth generation, and the values of median lifespan reached a plateau. After eight generations, the lifespan values of irradiated populations exceeded all the control values. Practically in all generations in the isogenic line Oregon-R spa, the lifespan increased after irradiation compared with non-irradiated controls. This is possibly due to a positive effect of radio-induced heterogeneity on the lifespan of the isogenic strain. Thus, chronic irradiation led to the violation of the natural cyclic dynamics of the lifespan in heterogeneous strains and to increasing lifespan in all generations of the isogenic strain.