Fig. 1.

Experimental strategy. The haploid BY4741 (MATa) WT strain was transformed to delete the listed mutator gene(s) (Table 1). Next, four parallel long-term mutation accumulation (MA) lines were derived from each parental strain, by performing up to 100 single cell bottleneck passages (G₁₀₀), on growth on a nonselective rich medium [yeast extract/peptone/dextrose (YPD) plate] at 30 °C. The spots present in the G_25-100 lines symbolically represent the acquired mutations. Next-generation sequencing (NGS) of the WT and final passaged strains was performed (Fig. S1).