Cloning and mapping of the RAD50 gene of Saccharomyces cerevisiae

The RAD50 gene was cloned as a 4.8 kb fragment in the 2 μ derived plasmid pFL1. The gene resides in a 3.9 kb segment that was subcloned into the plasmid YRp7. The cloned gene complements the deficiency caused by the rad50-1 mutation with respect to γ-rays, MMS resistance and UV-induced mitotic recombination. Restoration of the Rad⁺ phenotype occurs when the cloned gene is on a freely replicating multiple-copy plasmid or in the integrated form. Mapping of the cloned gene following integration of the 2 μ plasmid, and of the subclone in plasmid YRp7, showed it to be located on the left arm of chromosome XIV. Tetrad analysis of various crosses involving tow different strains carrying rad50-1 showed the mutation to map next to pet2 on chromosome XIV, and not on the right arm of chromsome IV, as previously published.