Gene–Environment Correlation as a Source of Stability and Diversity in Development

Abstract

As free-ranging organisms develop, their phenotype at any particular point is an influence on the selection of future environments. New and more varied environments make once-similar individuals more different, and those increased differences cause even greater differences in environment. Reciprocal effect processes of this kind introduce nonindependence and nonlinearity into developmental models, violating the assumptions of simple linear regression models or the classical twin model. Nevertheless, twins are a crucial laboratory for understanding the environmental differentiation of genetically related individuals, informing developmental science for singletons as well.