Education, reproductive success and longevity: a Mendelian randomization study

It has been suggested that educational attainment is under negative selection. Recent genetic findings make it possible to directly test natural selection by analysing whether genetic variants robustly associated with various... [ view full abstract ]

It has been suggested that educational attainment is under negative selection. Recent genetic findings make it possible to directly test natural selection by analysing whether genetic variants robustly associated with various traits are also associated with reproductive success. We therefore investigated whether individuals with greater genetically predicted educational attainment had fewer offspring. Such a relationship is compatible with a slow life history strategy where less effort is directed towards reproduction in conjunction with increased longevity. We performed Mendelian Randomization analyses in UK Biobank to assess causal associations between educational attainment and both number of offspring (N = 113,518) and longevity (N = 44,089), using single nucleotide polymorphisms associated with years of education (p < 5 × 10-8). As predicted, educational attainment was negatively associated with number of offspring (mean difference: -0.09, 95% CI: -0.12, -0.06 per SD increase in education score) and positively associated with longevity (mean difference: 0.07, 95% CI: 0.04, 0.10 per SD increase in education score). Results were similar when males and females were analysed separately. Our results suggest educational attainment is under negative selection, as individuals with greater genetically predicted educational attainment have fewer offspring.