Role of Gene-Environment Correlations during Early and Middle Childhood

A large body of research has identified the importance of the family environment for influencing child development. Nonetheless, variation in the exposure to environmental risk factors is typically characterized as a random phenomenon, where the mechanisms linking environmental risk factors to behavioral development are believed to operate outside of the individual. Genetically informed research derived from the fields of behavior genetics and molecular genetics, however, suggests that genetic factors can account for some of the variation in the environment. Specifically, this line of work recognizes the potential for one’s genetic propensities to help select, create, and modify the exposure to various environments. Building off of this body of research, the current dissertation seeks to examine whether a number of single genetic variants, as well as polygenic scores comprised of groups of genes, can help account for variation in environmental exposures during early and middle childhood. Towards this end, the genotypic data available for mothers and children of the Fragile Families and Child Wellbeing Study (FFCWS) will be used to guide the estimation of the variation in a number of familial environments over time. The evidence of genetically influenced environmental variation, moreover, will be contextualized within a developmental framework. The results of the current dissertation revealed three main findings. First, single genetic variants of the dopaminergic and serotonergic gene systems, as well as their polygenic scores, explained a significant amount of variation in familial environments during early and middle childhood. Second, gene-environment correlations were found to vary in importance during the early life course, which aligns with previous recommendations to examine such relationships through a developmental lens. Third, the single genetic variants and polygenic scores found to explain significant variation in measures of the family environment over multiple time points did not significantly differ from one another across the early life course. The findings are contextualized within the existing literature and recommendations for future research, as well as policy implications, are discussed.