Genetic activity of bleomycin: differential effects on mitotic recombination and mutations in yeast.

The genetic effects of the antitumor antibiotic, bleomycin were studied in different strains of Saccharomyces cerevisiae. It was observed that the drug induced a high frequency of mitotic recombination and gene conversion. In contrast, it produced only a few mutations from adenine independence to adenine dependence and histidine dependence (a missense mutant) to histidine independence. In the strains carrying ochre-suppressible auxotrophic markers, no prototrophs were induced by this drug. The results indicating the specific activity of bleomycin are discussed and, in this connection, the usefulness of yeast as a test organism in mutagenicity screening is emphasized.