Meeting Abstract

P2.65  Jan. 5  Genetic variation in pleiotropy PAVLICEV, M.*; KENNEY-HUNT, J. P.; NORGARD, E. A.; CHEVERUD, J. M.; Washington University, St. Louis; Washington University, St. Louis; Washington University, St. Louis; Washington University, St. Louis pavlicev@pcg.wustl.edu

The phenotype can be described as hierarchical complexes of integrated units. One aspect of the genetic architecture of such units is pleiotropy, which may result in covariation among units due to the effects of the common genes. While covariance structure depicts the relationships between the traits in a population, its evolutionary relevance depends upon the heritability of the covariance between the traits. The potential of the phenotype to be molded by selective forces is constrained in part by the stability of the genetic covariance structure over time. In order for modular structures to evolve, their genetic covariance structure must be variable. Much of the work on modularity in phenotypic evolution focuses on the discontinuous nature of modular phenotypes. We concentrate on continuous population-level genetic variation in the modularity of adult phenotypes. In this work we address the variation in pleiotropy by mapping relationship QTLs (rQTL) for limb bone lengths in relation to weight at necropsy in an F2 generation of a cross between two inbred mouse strains. These loci are identified as having an effect on the relationship between pairs of traits rather than simply contributing variation to the trait itself. Thus when considering morphological traits, such loci affect shape, or as in this case, allometry. Pair-wise relationships between traits can be affected by rQTL in two ways: by affecting one trait, but not the other; or second, by differential effects on both traits, in which case rQTL is pleiotropic. We studied the differential effects of pleiotropic rQTLs on the relationships between phenotypic traits belonging to the domain of these loci.