PT  - JOURNAL ARTICLE
AU  - Joshua S. Bloom
AU  - Iulia Kotenko
AU  - Meru J. Sadhu
AU  - Sebastian Treusch
AU  - Frank W. Albert
AU  - Leonid Kruglyak
TI  - Genetic interactions contribute less than additive effects to quantitative trait variation in yeast
AID  - 10.1101/019513
DP  - 2015 Jan 01
TA  - bioRxiv
PG  - 019513
4099  - http://biorxiv.org/content/early/2015/10/08/019513.short
4100  - http://biorxiv.org/content/early/2015/10/08/019513.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 debate. 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.