Abstract
Outcomes of interest to demographers—fertility; health; education—are the product of both an individual’s genetic makeup and his or her social environment. Yet Gene × Environment research (GxE) currently deploys a limited toolkit on the genetic side to study gene-environment interplay: polygenic scores (PGS, or what we call mPGS) that reflect the influence of genetics on levels of an outcome. The purpose of the present paper is to develop a genetic summary measure better suited for GxE research. We develop what we call variance polygenic scores (vPGS), or polygenic scores that reflect genetic contributions to plasticity in outcomes. The first part of the analysis uses the UK Biobank (N ∼ 326,000 in the training set) and the Health and Retirement Study (HRS) (N = 10,524) to compare four approaches for constructing polygenic scores for plasticity. The results show that two widely-used methods for discovering which genetic variants affect outcome variability fail to serve as distinctive new tools for GxE. Then, using the polygenic scores that do capture distinctive genetic contributions to plasticity, we analyze heterogeneous effects of a UK education reform on health and educational attainment. The results show the properties of a new tool useful for population scientists studying the interplay of nature and nurture and for population-based studies that are releasing polygenic scores to applied researchers.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
The authors would like to thank members of the Conley Biosociology Lab and the University of Wisconsin Social Genomics workshop for helpful feedback on the project. Results from this research were presented earlier at the National Institute on Aging supported 2018 Integrating Genetics and Social Science Conference (R13-AG062366) at the University of Colorado, Boulder.
1 Put differently, a polygenic score trained in societies where those constraints were attenuated or absent would poorly predict education before an expansion of schooling and then predict in an improved way — i.e. show increased genetic penetrance — once access to formal education was opened up.
