Systematic Analysis of Suppressor Mutations in S. cerevisiae Strains with Deleted Genome Integrity Genes

The effects of a mutation in one gene can occasionally be suppressed by mutation in another gene. Genetic suppression indicates functional relationships and provides clues about the mechanism and order of action in genetic pathways. Here I explored the existing yeast deletion collection to identify suppressor relationships. The collection was released in 2000 and it is known that some strains in the collection have acquired mutations. Whole genome sequencing of 48 yeast deletion strains corresponding to 26 genome integrity genes was performed. High-throughput sequencing revealed a broad mutational spectrum including point mutations, indels, and copy number variations. I identified and experimentally validated two new suppressor mutations (sgs1 mutations in both top3Δ and rmi1Δ strains) corresponding to gene pairs with previously known suppressor relationships. Thus, high-throughput sequencing and analysis of yeast deletion strains can identify suppressor mutations. The resulting genome sequences also provide a baseline for future laboratory evolution experiments.MAS