VI.—Mutation and Lethal Effects of Ultra-Violet Irradiation onDrosophila

Abstract

In a recent paper (Mackenzie and Muller, 1940) a brief account was given of certain methods employed to obtain a favourable mutation rate in male adult Drosophila. These methods were largely empirical, and a detailed account of their development, together with a discussion of their significance, seemed rather beyond the scope of the paper, which dealt principally with the possible chromosome rearrangements which could be brought about by ultra-violet light. Hence only the average of a large number of experiments was given. In this paper it is proposed to give a fuller account of the influence of ultra-violet rays on Drosophila, and to compare the somatic effects, which are directly lethal, with the spermatic effects, which occur in the surviving insects and are observed as mutations in the offspring.