Storage effects on sex-chromosome losses induced by triethylene melamine (TEM) and ethyl methane-sulfonate (EMS) in Drosophila melanogaster.

Abstract

Drosophila spermatozoa treated with triethylene melamine (TEM) or ethyl methanesulfonate (EMS) were stored in untreated females, and changes in the frequency of sex-chromosome losses were determined. In some experiments, an enhancing effect of storage on sex-chromosome losses was observed, while in other experiments the effect disappeared. The effect of storage was found to be dependent on the strains used. In the case of TEM, the effect was dose-dependent. At low doses the yield of sex-chromosome losses increased markedly after storage, while at high doses the enhancing effect disappeared. When enhancing effects were observed, the increase in yield after storage was marked for double marker losses (loss of both terminal markers on the doubly marked Y) than for single marker losses (loss of one of the two markers). These results suggest that sex-chromosome losses potentially respond to storage treatment, but the effect can be modified by some factors. The present findings are discussed in terms of potential break hypothesis.