Developmental associations between traits: Covariance and beyond

Statistical associations between phenotypic traits often result Front shared developmental processes quid include both covariation between the trait values and more complex associations between higher moments of the Joint distributions of traits. In this article, an analytical technique for calculating the covariance between traits is presented oil the basis of (1) the distribution of underlying genetic fund environmental variation that jointly influences the trails and (2) the mechanics of how these underlying factors influence the development of each trait. It is shown that epistasis can produce patterns of covariation between traits that are not seen in additive models. Applying this approach to it trait in Parents and the same trait in their offspring allows its to study the consequences of epistasis for die evolution of additive genetic variance and heritability. This analysis is then extended to the study of more complicated associations between traits. It is shown that even traits that are not Correlated may exhibit developmental till associations that influence their-joint evolution.