[Effect of pulse and prolonged x-rays in air and in nitrogen on the frequency of sex-linked recessive lethal mutations in Drosophila melanogaster].

The effect of X-irradiation on the frequency of recessive lethal mutations in Drosophila melanogaster sperm cells is studied. Drosophila males were X-irradiated in air and nitrogen in three units with doses rates of 4 X 10(9), 10(11) and 1.7 rad/sec at a dose of 2000 rad. It is found that the mutation frequency after the pulse irradiation was almost twice as low as that after prolonged irradiation. The oxygen effect is eliminated under pulse irradiation, and the data on pulse irradiation in air are similar to those on irradiation at a low dose rate in nitrogen. The data obtained are explained by the presence of short-lived oxygen-dependent damages which are not realized under pulse irradiation due to the lack of oxygen in the track volume.