Molecular specificity of x-radiation and its repair in Saccharomyces cerevisiae

Molecular specificity of soft X-radiation has been studied in yeast by analyzing the transitions UAA reversible UAG and nonsense → sense mutations in the codon tyr7-1. Synchronized cell populations in the most radiosensitive and radioresistant stages were compared: they did not show any qualitative or quantitative differences in their sensitivities to the mutagenic action of X-rays. It is concluded that repair mechanisms, which remain unexpressed in the sensitive cells, do not affect point mutations of the base-substitution type