Heat shock stimulates genomic instability and phenotypic variations in yeast

Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genomic instability. In this study, heat-shock-induced genomic alterations were explored in the heterozygous diploid yeast strain JSC25-1. In combination of the whole-genome microarray, the patterns of chromosomal instability induced by heat shock could also be explored at a whole genome level. Using this system, we found heat-shock treatment resulted in hundreds-fold higher rate of genomic alterations, including aneuploidy and loss of heterozygosity (LOH). The JSC25-1 cells were cultured in liquid YPD to an OD600 of 0.25 (initial OD600 was 0.05), then cells at a concentration of 1 OD600 were heat-shocked at 52℃ for 4 min. The treated cells were then plated on YPD plates to allow colonies formation at 30℃ for 3 days. A total of 21 independent colonies (named JP1-JP21) were randomly selected for whole-genome microarray analysis.