Estimating the genotypic intelligence of populations and assessing the
impact of socioeconomic factors and migrations.
Abstract
Factor analysis of allele frequencies was used to identify signals of
polygenic selection on human intelligence. Four SNPs which reached
genome-wide significance in previous meta-analyses were used. Allele
frequencies for 26 population were obtained from 1000 Genomes. The
resulting factor scores were highly correlated to average national IQ
(r=0.92). A regression of IQ differences between subcontinental groups
on the 4 SNPs g factor and an index of genome-wide genetic distances
showed the former was an independent and significant predictor (Beta=
1.14), whereas genome-wide distances lost all predictive power. This
finding suggests that the relationship between the 4 SNPs g factor and
IQ is due to natural selection on a specific phenotype and not the
result of a spurious correlation arising from genome-wide evolutionary
processes such as random drift or migrations. A regression of IQs on
genetic factor scores of developed countries was used to estimate the
predicted genotypic IQs of developing countries. The residuals
(difference between predicted and actual scores) were negatively
correlated to per capita GDP and Human Development Index, implying that
countries with low socioeconomic conditions have not yet reached their
full intellectual potential.