Induction of male recombination in Drosophila melanogaster by injection of extracts of flies showing male recombination

Abstract

MORGAN^1,2 was the first to report that no spontaneous recombination occurs in males of Drosophila melanogaster. Since then recombination has been induced in D. melanogaster males by various treatments³, for example, X rays. In an attempt to study the control of recombination in D. melanogaster, Reddi et al.⁴ injected males with ovarian extracts and, surprisingly, induced recombination. Subsequent attempts to repeat this experiment failed^5,6. It is known that some natural populations of D. melanogaster show spontaneous male recombination^7–10, and it has been suggested that this may be caused by episomes or viruses^8,9,11. It is therefore possible that these male recombination-inducing factors could be transferred by injection, and that the failure to reproduce these results⁴ might have been due to the use of strains lacking such factors. We have therefore tested whether or not male recombination could be induced by injecting extracts of flies from strains showing male recombination into flies lacking male recombination.