An attempt to determine the relative genetic efficiency of fast neutrons by the induced reciprocal translocations in mouse spermatogonia

Sexually mature male mice of C57BL line are irradiated over a period of 10, 70 or 720 hours with 25 rad neutrons from plutonium-berilium source. Another series of mice is exposed to 200 rad gamma-rays from radium source, distributed over the same three lengths of time. The cytogenetic analysis of primordial spermatocytes in diakinesis metaphase I on the 60th post-irradiation day disclosed chromosomal translocations resulting from injury to the heriditary structures of the spermatogonial cells. A dose power variation by one or two orders exerts no influence on the radiation effect. Under these conditions the relative genetic effectiveness of neutrons with an average energy of 41 MeV was 11 to 20 tending to be higher at decreasing the dose power. (Ch.K.)