Gene expressivity on educational attainment increases with age, and then slows

Abstract

The relative contributions of genetic and environmental influences to phenotypes vary with age. A Wilson effect denotes age-related increases in heritability, and an anti-Wilson effect the opposite (specifically a decline in heritability in late life). To date, few molecular-genetic studies of these effects have been conducted. Here we tested for Wilson effects on educational attainment (EA), leveraging a dataset with a wide age range (18–60 years) and polygenic scores (PGSs) for EA. Using a two-way interaction model, we estimated changes in the predictive power of one such PGS (specifically EA3) for EA as a function of aging. We found that the PGS predicted EA better in older participants (semi-partial regression coefficient [sr] = 0.05, 95%CI = 0.00, 0.10), potentially consistent with a Wilson effect. The effect of EA3² had a further independent negative effect on EA in older participants (sr = −0.06, 95%CI = −0.11, −0.01), indicating that the Wilson effect slows with greater age. The findings suggest that PGS expressivity increases as individuals attain an educationlevel in line with their abilities and preferences as they age. But past a relatively early age (in almost all cases), the maximal level of education in line with genetic liability is reached, and PGS expressivity plateaus. Beyond this point PGS expressivity may even start to decline (an anti-Wilson effect), which, rather than reflecting the developmental dynamics of EA itself, could result from the known tendency for episodic and semantic memory to decline later in life, leading to misrecollection of certain life events (which could cause erroneous recall of level of EA). Caution is warranted in interpreting these results, however, since, owing to the cross-sectional nature of our study, there are potential confounding factors at play.