(A) Late logarithmically growing cells (5×10⁷ cells/ml) of tetraploid strains with 4 copies (WT) or one copy (simplex) of MCD1, RAD50 and RAD51 as well as mcd1-1 diploid cells were spotted on YPDA plates. The control and irradiated plates (80 krad) were incubated for two days at 30°C. (B) Logarithmically growing cultures of WT, and simplex strains (presented as “S”) for MCD1, RAD50 and RAD51 were harvested in SDS PAGE sample buffer and separated on SDS PAGE. Protein amounts were determined by western blot analysis using antibodies; histone H3 (presented as “H3”) was used as a loading control. The normalized intensity of each protein in the simplex strain was divided by the normalized intensity in WT to give the simplex/WT ratio.