Genetic architecture of growth traits revealed by global epistatic interactions.

Epistasis has long been recognized as fundamentally important in understanding the structure, function, and evolutionary dynamics of biological systems. Yet, little is known about how it is distributed underlying specific traits. Based on a global map of epistatic interactions in baker's yeast, Saccharomyces cerevisiae, we show that epistasis is prevalent (∼13% increase from random expectation) and displays modular architecture among genes that underlie the same growth traits. More interestingly, our results indicate that hub genes responsible for the same growth traits tend to link epistatically with each other more frequently than random expectation. Our results provide a genome-wide perspective on the genetic architecture of growth traits in a eukaryotic organism.