Saturday, September 19, 2015

SNP hits on cognitive ability from 300k individuals

James Lee talk at ISIR 2015 (via James Thompson) reports on 74 hits at genome-wide statistical significance (p < 5E-8) using educational attainment as the phenotype. Most of these will also turn out to be hits on cognitive ability.

To quote James: "Shock and Awe" for those who doubt that cognitive ability is influenced by genetic variants. This is just the tip of the iceberg, though. I expect thousands more such variants to be discovered before we have accounted for all of the heritability.
James J Lee

University of Minnesota Twin Cities
Social Science Genetic Association Consortium

Genome-wide association studies (GWAS) have revealed much about the biological pathways responsible for phenotypic variation in many anthropometric traits and diseases. Such studies also have the potential to shed light on the developmental and mechanistic bases of behavioral traits.

Toward this end we have undertaken a GWAS of educational attainment (EA), an outcome that shows phenotypic and genetic correlations with cognitive performance, personality traits, and other psychological phenotypes. We performed a GWAS meta-analysis of ~293,000 individuals, applying a variety of methods to address quality control and potential confounding. We estimated the genetic correlations of several different traits with EA, in essence by determining whether single-nucleotide polymorphisms (SNPs) showing large statistical signals in a GWAS meta-analysis of one trait also tend to show such signals in a meta-analysis of another. We used a variety of bio-informatic tools to shed light on the biological mechanisms giving rise to variation in EA and the mediating traits affecting this outcome. We identified 74 independent SNPs associated with EA (p < 5E-8). The ability of the polygenic score to predict within-family differences suggests that very little of this signal is due to confounding. We found that both cognitive performance (0.82) and intracranial volume (0.39) show substantial genetic correlations with EA. Many of the biological pathways significantly enriched by our signals are active in early development, affecting the proliferation of neural progenitors, neuron migration, axonogenesis, dendrite growth, and synaptic communication. We nominate a number of individual genes of likely importance in the etiology of EA and mediating phenotypes such as cognitive performance.
For a hint at what to expect as more data become available, see Five Years of GWAS Discovery and On the genetic architecture of intelligence and other quantitative traits.

What was once science fiction will soon be reality.
Long ago I sketched out a science fiction story involving two Junior Fellows, one a bioengineer (a former physicist, building the next generation of sequencing machines) and the other a mathematician. The latter, an eccentric, was known for collecting signatures -- signed copies of papers and books authored by visiting geniuses (Nobelists, Fields Medalists, Turing Award winners) attending the Society's Monday dinners. He would present each luminary with an ornate (strangely sticky) fountain pen and a copy of the object to be signed. Little did anyone suspect the real purpose: collecting DNA samples to be turned over to his friend for sequencing! The mathematician is later found dead under strange circumstances. Perhaps he knew too much! ...

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