X-RAY INDUCTION OF DUMPY MUTATIONS IN MATURE SPERM OF DROSOPHILA UNDER OXYGEN OR NITROGEN CONDITION

Abstract

A comparison was made on the relative frequencies of different kinds of dumpy mutations induced by X-rays in mature sperm under oxygen and nitrogen conditions.
The results indicate that (1) the yield of ov and olv exceptions (complete) under oxygen condition is significantly higher than that obtained after the same exposure under nitrogen, thus relatively high O.E.R. value of 3.11 is estimated; (2) the response of ol and lv exceptions (complete) is essentially similar to that of ov and olv ones, although the estimated O.E.R. value of 1.89 is relatively low; (3) however, no such difference is found in the yield of o and v exceptions (complete) between the two kinds of irradiation conditions. The O.E.R. value of 1.68 is calculated; (4) the overall frequency of mosaic dumpy mutations appears to be approximately the same, regardless of conditions irradiated. The O.E.R, value of 1.09 is estimated.
These observations indicate that the magnitude of oxygen effects may be different among the different kinds of dumpy mutations.