title: Genetic interactions contribute less than additive effects to quantitative trait variation in yeast.
abstract: 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.
authors.affiliation: Department of Human Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.|Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Bloom
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540, USA.
authors.forename: Iulia
authors.initials: I
authors.lastname: Kotenko
authors.affiliation: Department of Human Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Meru J
authors.initials: MJ
authors.lastname: Sadhu
authors.affiliation: Twist Bioscience, San Francisco, California 94158, USA.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Treusch
authors.affiliation: Department of Human Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Albert
authors.affiliation: Department of Human Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.|Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, California 90095, USA.|Department of Biological Chemistry, University of California, Los Angeles, California 90095, USA.
authors.forename: Leonid
authors.initials: L
authors.lastname: Kruglyak
mesh_terms: D002874:Chromosome Mapping; D004843:Epistasis, Genetic; D014644:Genetic Variation; D005838:Genotype; D010641:Phenotype; D040641:Quantitative Trait Loci; D012441:Saccharomyces cerevisiae / Q000235:genetics*