UK Biobank Results.

Results of own educational attainment regressed on (A) own genotyped polygenic risk score (PRS) and imputed parental PRS in sibling pairs, (B) own genotyped PRS and genotyped maternal PRS in mother-offspring duos, (C) own genotyped PRS and genotyped paternal PRS in father-offspring duos, and (D) own genotyped PRS, genotyped maternal PRS and genotyped paternal PRS in parent-offspring trios. All analyses were corrected for sex, year of birth and the first five principal components (PC) from the UK Biobank GWAS data. Sex was coded as 1 and 0 for males and females respectively. PRS were constructed using 1264 SNPs associated with education attainment identified in Lee et al. (2018). A sensitivity analysis was performed for (A) using PRS constructed using 72 SNPs identified in Okbay et al. (2016).