[Induction of transposition of MGE Dm412 using gamma-irradiation of an isogenic line of Drosophila melanogaster].

In an isogenic line of Drosophila, transpositions of mobile genetic elements (MGE) Dm412 were induced by gamma-radiation at doses of 300, 800, and 1300 R. The rates of induced transpositions were (for each dose, respectively) 3.9 x 10(-3), 1.0 x 10(-2), and 1.87 x 10(-2) events per occupied site per haploid genome of the isogenic line per generation. Thus, the transposition rate increased linearly with the radiation dose. The specific rate of gamma-radiation-induced transpositions was (1.3 +/- 0.6) x 10(-5) per occupied site per haploid genome of the isogenic line per Roentgen per generation. gamma-radiation-induced hot transposition sites and haplotypes, very similar to those induced by heat shock, were found. It was suggested that the mechanism of temperature induction than to the direct mutational effect of gamma-radiation. Estimates of induced transposition rates per genome for each dose were calculated as 1.1, 3.0, and 5.6 events, respectively, per genome per generation. This level probably corresponds to the subthreshold level of genomes near the "catastrophic border of transpositional losses."