Comparison of the effects of ultraviolet light and ethylmethanesulphonate upon the frequency of mitotic recombination in yeast

Summary Host-cell reactivation of gamma-irradiated phage T1 in strains of E. coli K-12 has been compared with HCR of UV-irradiated phage in these same strains and with the radiation sensitivities of these strains (Fig. 1–4). The pattern of the HCR of gammairradiated phage in these strains is like that of the HCR of UV-irradiated phage. HCR in strains whose genotype is uvr⁺rec^- is like that of the wild type; whereas, HCR is minimal in strains which are uvr^-. It is suggested that some type of gamma-ray-induced base damage in phage DNA is repaired in uvr⁺ strains.This work was supported by the United States Atomic Energy Commission Contract No. AT(11-1)-1686. — This is report No. COO-1686-6.Supported in part by the United States Public Health Service Training Grant No. 5T1 RH-80-02(67).