Exploring gene-environment interactions: Socioregional moderation of alcohol use

Examples of gene-environment interaction in human behavioral data are relat ively rare; those that exist have used simple, dichotomous measures of the environment. The authors describe a model that allows for the specification of more continuous, more realistic variations in environments as moderator s of genetic and environmental influences on behavior. Using data from a po pulation-based Finnish twin study, the authors document strong moderating e ffects of socioregional environments on genetic and environmental influence s on adolescent alcohol use, with nearly a five-fold difference in the magn itude of genetic effects between environmental extremes. The incorporation of specific environmental measures into genetically informative designs sho uld prove to be a powerful method for better understanding the nature of ge ne-environment interaction and its contribution to the etiology of behavior al variation.