A review of intelligence GWAS hits: Their relationship to country IQ and the issue of spatial autocorrelation

摘要

Published Genome Wide Association Studies (GWAS), reporting the presence of alleles exhibiting significant and replicable associations with IQ are reviewed. The average between-population frequency (polygenic score) of nine alleles positively and significantly associated with intelligence is strongly correlated to country-level IQ (r = .91). Factor analysis of allele frequencies furthermore identified a metagene with a similar correlation to county IQ (r = .86). The majority of the alleles (seven out of nine) loaded positively on this metagene. Allele frequencies varied by continent in a way that corresponds with observed population differences in average phenotypic intelligence. Average allele frequencies for intelligence GWAS hits exhibited higher inter-population variability than random SNPs matched to the GWAS hits or GWAS hits for height This indicates stronger directional polygenic selection for intelligence relative to height. Random sets of SNPs and Fst distances were employed to deal with the issue of autocorrelation due to population structure. GWAS hits were much stronger predictors of IQ than random SNPs. Regressing IQ on Fst distances did not significantly alter the results nonetheless it demonstrated that, whilst population structure due to genetic drift and migrations is indeed related to IQ differences between populations, the GWAS hit frequencies are independent predictors of aggregate IQ differences. (C) 2015 Elsevier Inc. All rights reserved.