“Familial Influences on Neuroticism and Education in the UK Biobank”, 2019-03-20 (; similar):
Genome-wide studies often exclude family members, even though they are a valuable source of information. We identified parent-offspring pairs, siblings, and couples in the UK Biobank and implemented a family-based DNA-derived heritability method to capture additional genetic effects and multiple sources of environmental influence on neuroticism and years of education. Compared to estimates from unrelated individuals, heritability increased 10% → 27% and 19% → 57% for neuroticism and education respectively by including family-based genetic effects.
We detected no family environmental influences on neuroticism, but years of education was substantially influenced by couple similarity (38%). Overall, our genetic and environmental estimates closely replicate previous findings from an independent sample, but more research is required to dissect contributions to the additional heritability, particularly rare and structural genetic effects and residual environmental confounding.
The latter is especially relevant for years of education, a highly socially-contingent variable, for which our heritability estimate is at the upper end of twin estimates in the literature. Family-based genetic effects narrow the gap between twin and DNA-based heritability methods and could be harnessed to improve polygenic prediction.