DNA double-strand breaks and the RAD50-RAD57 genes in Saccharomyces

The yeast Saccharomyces provides a powerful system for investigating the biological effects of ionizing radiation, and studies have identified double-strand breaks in DNA as probably of critical importance in determining lethality. These breaks are normally repaired by a recombinational mechanism, but in the absence of repair a single break may be lethal to the cell. Genetic and molecular analysis of the eight genes known as RAD50 to RAD57 has revealed much about recombinational repair. These genes are also of central importance in other processes including meiosis and may be of general significance in understanding radiation responses in eukaryotes.