Figure 3.

Genetic dissection of the chromosome IV duplication’s effect on hydrogen peroxide tolerance. (A) PCDs were staggered nearly every 50 kb along chromosome IV-R in a BY × RM derived aneuploid. Phenotyping of partially aneuploid strains generated by PCD identified a single genomic interval with a large effect on hydrogen peroxide tolerance when strains were examined at a dose of 7.5 mM. This ∼40 kb region contains 23 genes and three dubious ORFs. (B) Two additional PCD strains were generated within the previously mentioned window and examined at 7.5 mM. This narrowed the interval to 7 kb that contained five genes and a dubious ORF. (C) Individual gene deletions revealed that TSA2 is largely responsible for the increase in tolerance conferred by duplication of chromosome IV-R. In (A and B), representative images of colonies grown at 7.5 mM of hydrogen peroxide are shown next to their associated PCD strains; numbers adjacent to the telomere indicate the starting position of each PCD on chromosome IV. In (C), representative images of colonies grown at 7.5 mM of hydrogen peroxide are again shown next to their associated individual gene deletion strains, with deleted regions indicated by gaps on the duplicated chromosome.