Mitomycin C induces genomic rearrangements involving transposable elements in Drosophila melanogaster

Summary Mitomycin C was injected into the abdomen of male flies of the y² sc¹ w^aG strain of Drosophila melanogaster. They were mated with females bearing attached-X chromosomes, and the male offspring (F₁) were analysed for the appearance of mutations in the X chromosome. We observed y¹ and sc⁺ reversions induced either by excision of mdg4 (gypsy) with retention of one long terminal repeat (LTR) or by insertion of a foreign sequence into mdg4, partial reversion of the w^aG mutation, w^aGw^aGd, and unstable f mutations. The overall mutation frequency was considerably higher than in control flies of the y² sc¹ w^aG strain. Possible mechanisms of genomic rearrangements induced by Mitomycin C, in particular the role of homologous recombination, are discussed.