(D) Effect of the rad54∆ and rad52∆ mutations in spontaneous and UV-induced mutagenesis. The frequency of spontaneous and UV-induced forward mutagenesis at the CAN1 locus was determined by irradiating or not cells plated onto solid medium after the corresponding dilutions (SMM and SMM with canavanine to calculate total and mutant cells, respectively). Cell viability (right panel) was calculated from total irradiated cells relative to non-irradiated cells. The mean and SEM of 6 independent fluctuation tests are shown. Two asterisks represent a p-value <0.01, according to a two-way ANOVA followed by a Bonferroni test. 