Polygenic selection on educational attainment
The genetic variants identified by two large GWAS of educational attainment were used to test a polygenic selection model.
Average frequencies of alleles with positive (Beta) effect on the phenotype (polygenic scores) were compared across populations and racial groups using data from 1000 Genomes and ALFRED. Strong correlations between polygenic scores and population IQ were found (r>0.8). Moreover, the polygenic score obtained from the two independent GWAS exhibited a strong correlation (r= 0.83), even after pruning for linkage disequilibrium.
Factor analysis revealed that most alleles loaded on a single factor, which in turn was strongly correlated to population IQ.
Polygenic and factor scores survived control for phylogenetic autocorrelation, although the latter’s net effect on population was stronger (Betas= 0.361 and 0.861, respectively).
Results obtained from ALFRED data were similar and revealed a peak in polygenic and factor scores among East Asians (60.8% and 1.06, respectively) and a nadir among Africans and Native Americans (44.9%,44.1% and -1.47, -0.493, respectively).
Geographic distance from Eastern Africa (assuming an origin of modern humans there) was only weakly predictive of factor and polygenic scores (r= 0.21-0.29).