X-ray Induced Mutations in Spermatogonial Cells of Drosophila and Their Dose-frequency Relationship.

INTEREST in the mutability of spermatogonial cells has increased in recent years, primarily due to the demonstration of an X-ray intensity effect on these cells in the mouse (RUSSELL, RUSSELL, and KELLY 1958; RUSSELL 1960). Relatively few mutation experiments in Drosophila have utilized these cells compared to sperm and spermatid cells, and no large scale dose-frequency study has been carried out on spermatogonia. Because of the implications to induced genetic effects on human immature germ cells, it seemed desirable to determine the dosefrequency response of Drosophila spermatogonia to irradiation. These studies developed as an outgrowth from experiments considering the possibility of reparation of X-ray damage (ABRAHAMSON 1961) and because very preliminary data (unpublished) suggested that there might be a falling off of the curve at higher doses indicating the possibility of cell heterogeneity; we therefore sought more information on this subject. This paper presents some of the data discussed in an earlier preliminary communication ( ABRAHAMSON and FRIEDMAN 1962) .