Genetic analysis of gamma-ray mutagenesis in yeast. II. Allele-specific control of mutagenesis.

We find that partially different sets of gene functions are required for the production of different kinds of mutations induced by 60Co gamma rays in Saccharomyces cerevisiae. This observation is very similar to others made previously with respect to UV mutagenesis (LAWRENCE and CHRISTENSEN 1978a,b, 1979) and confirms the conclusion that such distinctive patterns of genetic control reflect properties of the test alleles and their genetic locations, rather than the kinds of lesions required to revert them. The data also support the model of mutagenic repair outlined in the first paper of this series (McKee and LAWRENCE 1979), in which partially different sets of gene functions are required for the production of different kinds of mutations, the formation of mutations at different genetic sites and the induction of mutations by different mutagens.