ULTRAVIOLET-INDUCED PHOTOREVERSIBLE GENETIC CHANGE OBSERVED IN HETEROZYGOUS DIPLOID SYSTEM OF YEAST-A STUDY OF THE UV ACTION SPECTRUM FOR INDUCTION AND OF THE PHOTOREVERSION

Abstract

The nature of genetic changes inducible by UV in diploid yeast was studied through action spectrum for the induction and photoreversion experiments. The results may be summarized as follows.(1) UV action spectrum for the induction is similar to the absorption spectrum of thymidine in shape.(2) Eighty per cent of the effect by 2, 800Å radiation is photoreversed.(3) Therefore, the primary events for both the induction and the photoreversion process may be explained by the double-strandedness of the gene DNA, although the kinetics of the photoreversion of whole- and fractional-type of change is not sufficiently clear.