The dosage suppressor screen entailed transformation of S. cerevisiae tgs1∆ cells with a 2-μ URA3 plasmid-based wild-type genomic DNA library and selection for Ura+ colonies that grew at 18°. Plasmid DNA was recovered from individual yeast colonies grown at 18° and then transformed into E. coli. Candidate suppressors were retransformed into the original tgs1∆ strain and tested for growth at 18°. Sequencing the insert junctions of the plasmids that retested faithfully revealed that the rescuing clones contained either TGS1 (as was to be expected) or one of two distinct extragenic suppressor loci, which we provisionally named DTS1 and DTS2, respectively (DTS = deletion of TGS1 suppressor). Note that whereas the 2-µ DTS1 or 2-µ DTS2 plasmids restored growth at 18°, compared to tgs1∆ cells carrying the empty 2-µ vector, neither 2-µ DTS1 nor 2-µ DTS2 was as effective as a TGS1 plasmid, as gauged by colony size (Figure 3).