THE PROCUREMENT OF BIOCHEMICAL MUTANTS OF SACCHAROMYCES BY THE SYNERGISTIC EFFECT OF ULTRAVIOLET RADIATION AND 2,6-DIAMINO PURINE

Abstract

Exposure of ultraviolet-irradiated, adenine-dependent haploid yeast to 2,6-diamino purine (an analogue of adenine) consistently gives rise to approximately 0.5% recessive biochemical mutants. This frequency is 22-fold higher than that obtained with either agent alone, and 150-fold higher than the spontaneous frequency. The distribution of mutants into nine discrete nutritional groups attests to the utility of the method for procuring relatively large numbers of different biochemical mutants. Several new gene markers for amino acid requirements are described, including one which controls an apparent single block for both lysine synthesis and respiratory competence.