High-resolution mapping of cis -regulatory variation in budding yeast

Significance Genetic variants affecting gene-expression levels are a major source of phenotypic variation. Using 85 diverse isolates of Saccharomyces cerevisiae , we mapped genetic variants that affect gene expression with 50-fold higher resolution than previously possible. By doing so, we were able to pinpoint likely causal variants and investigate their molecular mechanisms. We found that these genetic variants are generally under negative selection, but also that clinical yeast isolates have undergone positive selection for up-regulation of genes involved in biofilm suppression. Altogether, our results demonstrate the power of high-resolution mapping of genetic variants that affect gene expression, particularly in understanding the molecular mechanisms of regulatory variation and the natural selection acting on this variation.