Special thanks to commenter Carl Churchill for bringing this to my attention. Finally genes for IQ are being officially found, and ten years sooner than I thought!
Previous research had found genes for IQ but those findings failed to replicate in followup studies. There also been studies finding genes for dementia, which I consider genes for IQ, given the high correlation between old age cognitive function and early life cognition. But this is the first study I know of that directly found genes for IQ and replicated the findings.
The authors of the study are G Davies, RE Marioni, DC Liewald, WD Hill, SP Hagenaars, SE Harris, SJ Ritchie M Luciano, C Fawns-Ritchie1, D Lyall , Cullen, SR Cox, C Hayward , DJ Porteous, J Evans , AM McIntosh, J Gallacher, N Craddock, JP Pell, DJ Smith, CR Gale,and IJ Deary.
Here’s the abstract:
People’s differences in cognitive functions are partly heritable and are associated with important life outcomes. Previous genomewide association (GWA) studies of cognitive functions have found evidence for polygenic effects yet, to date, there are few replicated genetic associations. Here we use data from the UK Biobank sample to investigate the genetic contributions to variation in tests of three cognitive functions and in educational attainment. GWA analyses were performed for verbal–numerical reasoning (N = 36 035), memory (N = 112 067), reaction time (N = 111 483) and for the attainment of a college or a university degree (N = 111 114). We report genome-wide significant single-nucleotide polymorphism (SNP)-based associations in 20 genomic regions, and significant gene-based findings in 46 regions. These include findings in the ATXN2, CYP2DG, APBA1 and CADM2 genes. We report replication of these hits in published GWA studies of cognitive function, educational attainment and childhood intelligence. There is also replication, in UK Biobank, of SNP hits reported previously in GWA studies of educational attainment and cognitive function. GCTA-GREML analyses, using common SNPs (minor allele frequency40.01), indicated significant SNP-based heritabilities of 31% (s.e.m. = 1.8%) for verbal–numerical reasoning, 5% (s.e.m. = 0.6%) for memory, 11% (s.e.m. = 0.6%) for reaction time and 21% (s.e.m. = 0.6%) for educational attainment. Polygenic score analyses indicate that up to 5% of the variance in cognitive test scores can be predicted in an independent cohort. The genomic regions identified include several novel loci, some of which have been associated with intracranial volume, neurodegeneration, Alzheimer’s disease and schizophrenia.
Of course critics like commenter Chartreuse can still argue that these are only local genetic effects, so they need to be replicated in very different countries to prove they have an independent effect on IQ, but typically, with other traits, genes that are replicated in one population are replicated in very different continents and cultures, given enough sample size. I suspect the same will happen with IQ.