Using the genes parents do not transmit to offspring to test evidence for a parental social competence phenotype in education and social attainment

Measures of educational attainment (EA) confound parent and offspring genetics, causal family environments, and interactions of these. Here we present a new design capitalizing on the fact that parents pass, at random,... [ view full abstract ]

Measures of educational attainment (EA) confound parent and offspring genetics, causal family environments, and interactions of these. Here we present a new design capitalizing on the fact that parents pass, at random, 50% of their genome to a given offspring. This allows the creation of EA PRS (polygenic risk) scores for the parents using only alleles not transmitted to the offspring: A "virtual parent". The effect of non-transmitted alleles on offspring attainment was tested in 2,333 genotyped twins with high-quality measures school attainment at age 17 years. Four key findings were observed. First, the EA PRS and EA VP_PRS were empirically independent, validating the virtual-parent design. Second, in this family-based design, children’s own EA PRS significantly predicted their EA (β = 0.15), ruling out stratification confounds as a cause of the association of attainment with the EA PRS. Third, parent's PRS predicted their own SES (β = 0.20) Fourth, Non-transmitted alleles predicted offspring EA, and this indirect effect had 1/3 the magnitude of the direct offspring genetic-EA association. This effect was entirely mediated by parental SES. This suggests that the EA PRS codes as strongly for parental social competence as it does offspring EA, and that this competence phenotype exerts an indirect causal influence on the offspring EA extended phenotype. The virtual-parent method may be applied to clarify causality in other phenotypes where observational evidence suggests parenting may moderate expression of other outcomes.