THE EFFECT OF OXYGEN CONCENTRATION ON THE FREQUENCY OF INDUCED XO MALES AND NONDISJUNCTION FEMALES AFTER IRRADIATION OF DROSOPHILA MALES

Abstract

Studies were made on the effect of irradiation under different oxygen concentrations during various stages of spermatogenesis. By use of a dual purpose stock it was possible to study the frequency of induced XO males and induced non-disjunction between the paternal X and Y chromosomes. Drosophila, 0- 1 and 3-4 day old y/sup 16/ and sc/sup 8/Y males, were irradiated in commercial nitrogen or oxygen and mated to virgin y w sn females. A comparison between the yield of XO males after irradiation under anaerobic conditions and the corresponding data after treatment in air shows that a significantly lower rate of induced XO males is obtained after irradiation in N/sub 2/ atmosphere. The difference is most marked in mating periods corresponding to the period of highest sensitivity. The effect of commercial oxygen on the frequency of induced XO males after irradiation of 0-1 and 3-4 day old males is reversed as compared to the effect of air atmosphere. For 3-4 day old males irradiation in O/sub 2/ increases the yield of XO males. For both types of males almost no enhancing effect is obtained for mature spermatozoa after irradiation in O/sub 2/. it is concluded that it is not possiblemore » to talk about a common air/nitrogen ratio of radiosensitivity for irradiated Drosophila males, since there exists great variations between the different mating periods. For 3-4 day old males, irradiation under anoxia gives an almost total protection against induced non- disjunction. For 0-l day old males a reduction in the yield of non-disjunction females is observed, but still on the 8th day a rise in wild type females was observed. The relation between radiosensitivity and intra and/or intercellular oxygen available in the treated cells is discussed. (P.C.H.)« less