X-ray Sensitivity of Spermatogonia and Spermatozoa in Drosophila melanogaster

Abstract

IN a study of X-ray induced crossing-over in young spermatogonia of Drosophila melanogaster, Sävhagen (unpublished) has irradiated 17-hr.-old larvæ. These were heterozygous for a series of recessive marker genes in the third chromosome. After eclosion the males were tested during six successive mating periods of three days each. The frequency of males with cross-overs among their progeny decreased for every period. Synchronously the frequency of crossover per male with cross-overs increased. In all these mating periods the frequency of cross-overs of the total offspring was the same.