Induction of dominant lethality by X-rays in a radiosensitive strain of yeast

Abstract

Abstract X-Ray-survival curves of haploid, diploid, triploid and tetraploid yeast strains homozygous for the X-ray-sensitive mutation rad52 (previously xs1 are presented. These curves suggest that strains carrying the rad52 mutation may be more susceptible than wild type to X-ray-induced dominant lethal damage. For the crosses (+ × +, rad52 × rad52, + × rad52, rad52 × +) in which only one parent was irradiated, the relationships between zygote survival and X-ray dose were similar except for rad52 × rad52. In this cross a considerably higher frequency of dominant lethal damage was observed. This observation indicates that the rad52 mutant lacks a repair system for X-ray damage and is consistent with the proposal that unrepaired chromosome damage is the event which leads to dominant lethality and reproductive cell death.