BIOLOGICAL DAMAGE IN DEVELOPING GERM CELLS OF DROSOPHILA VIRILIS IN OXYGEN AND NITROGEN WITH 14-MEV NEUTRONS

Abstract

Germ cells of spermatogenesis were treated with accelerator neutrons of 14-mev energy in O2 and N2 atmospheres. Treatment with 999.5 rads of neutrons in O2 produced significant increases over the N2 values for translocations and dominant lethals in postmeiotic stages of cell development. In both gases the differential effect was greater in spermatids than in sperm. Dominant lethal damage also increased in sperm and spermatids with O2. In N2, there were no significant changes in dominant lethal values in postmeiotic cells. Sensitivity in chromosome breakage, measured as translocations, differed in the germ cell stages in both gases. In meiotic cells, higher dominant-lethal values were found with O2 than with N2. In spermatogonial cells, the lethal damage was similar in both gases. The pupal test indicated that some premeiotic cells were present in the testes resistant enough to survive neutron doses that produce complete lethality in postmeiotic cells. The surviving cells contained no dominant lethal damage and acted as stem or spermatogonial cells for repopulating the germ cells of the testes. The significance of these results.