Opportunities for improvement of phenotypic variability: influence of direct vs epistatic effects

Abstract Text: Genetic regulation of phenotypic variability has recently become a hot topic in quantitative genetics. Empirical evidence has shown that individual loci controlling phenotypic variability or “vQTL” can be mapped in population-based studies, and also that there are polygenic effects on the variability. In the breeding context, scientists have been investigating whether it is possible to select for phenotypic variability or uniformity, in order to better control the production quality. However, since apparent vQTL effects can be caused by various types of interactions, such as epistasis which influence the genetic variance, possibility of selection for phenotypic variability may not be guaranteed. Here, based on epistatic models, we theoretically analyze and discuss the selection for phenotypic variability. Our results indicate that such selection would be effective in changing the phenotypic variance via interaction effects only for a few special situations. 

Keywords: variation in phenotypic variability, one vs many loci, epistasis