Using parent-offspring pairs to estimate indirect genetic effects in education

In this study, we investigate indirect genetic effects (IGEs) in education using parent-offspring trios and pairs. We introduce a novel approach that uses phased data to include parent-offspring pairs in the transmitted/non-transmitted study design, which increases the statistical power to detect IGEs and generalizability of the results. We validate and apply this method in a family-based subsample of adolescents and adults from Lifelines Cohort Study in the Netherlands (N=6,147), using the latest genome-wide association study data on educational attainment to construct polygenic scores (PGS). Our results indicate IGEs play a role in education outcomes in the Netherlands: we found significant associations between the non-transmitted PGS and secondary school level in youth between 13-24 years old, and education attainment and years of education in adults over 25 years old (beta = 0.14, 0.17 and 0.26, respectively). We also examined IGEs by parent-of-origin, in which we found tentative evidence for larger maternal effects. In conclusion, we replicated previous findings and show that including parent-offspring pairs in addition to trios in the transmitted/non-transmitted design can benefit future studies of parental IGEs in a wide range of outcomes.
Keywords: indirect genetic effects, genetic nurture, educational attainment, intergenerational transmission