Mutation in Drosophila melanogaster Males Exposed to β-Radiation from Neutron-Activated Phosphorus-Bakelite Plaques

Abstract

In 1953 the author published a paper (1) on the mutagenic efficiency of radioactive phosphorus in P32-labeled, adult male Drosophila melanogaster. In this paper the conclusion was reached that the calculated value describing the absorption by the male gonad of energy liberated by decaying radiophosphorus in tissue is erroneously high. The experimental value obtained was only one-fifth the calculated value. It was assumed throughout the work that the relation between radiation dosage and induced sex-linked recessive lethal mutation frequency was the same for p-rays, X-rays, and ~y-rays, since earlier work by Zimmer et al. (2) with radium f-rays had pointed toward this conclusion. More recently, however, Kirby-Smith and Daniels (3), working with Tradescantia paludosa, have demonstrated conclusively that P32 -rays are only one-half as efficient as 0.2-A X-rays in producing chromosome breakage. Since chromosome breakage may be responsible in-part for the production of lethal mutations in Drosophila, this observation by Kirby-Smith and Daniels makes necessary a re-examination of the problem of the mutagenic efficiency of #-radiation in the fruit fly.