PT - JOURNAL ARTICLE AU - Joshua Bloom AU - Iulia Kotenko AU - Meru Sadhu AU - Sebastian Treusch AU - Frank W. Albert AU - Leonid Kruglyak TI - The role of genetic interactions in yeast quantitative traits AID - 10.1101/019513 DP - 2015 Jan 01 TA - bioRxiv PG - 019513 4099 - http://biorxiv.org/content/early/2015/05/19/019513.short 4100 - http://biorxiv.org/content/early/2015/05/19/019513.full AB - Genetic mapping studies of quantitative traits typically focus on detecting loci that contribute additively to trait variation. Genetic interactions are often proposed as a contributing factor to trait variation, but the relative contribution of interactions to trait variation is a subject of debate1–5. Here, we use a very large cross between two yeast strains to accurately estimate the fraction of phenotypic variance due to pairwise QTL-QTL interactions for 20 quantitative traits. We find that this fraction is 9% on average, substantially less than the contribution of additive QTL (43%). Statistically significant QTL-QTL pairs typically have small individual effect sizes, but collectively explain 40% of the pairwise interaction variance. We show that pairwise interaction variance is largely explained by pairs of loci at least one of which has a significant additive effect. These results refine our understanding of the genetic architecture of quantitative traits and help guide future mapping studies.