From The Telegraph:
Genes linked with problem-solving powers were linked to how well brain cells communicated
Sarah Knapton, science editor
12 MARCH 2018 • 5:52PM
Intelligence could be measured with a swab of saliva, or drop of blood, after scientists showed for the first time that a person’s IQ can be predicted just by studying their DNA.
Not sure this is “the first time” because it’s of course a question of how much IQ can be predicted.
In the largest ever study looking at the genetic basis for intelligence, researchers at the University of Edinburgh and Harvard University discovered hundreds of new genes linked to brain power.
Now by studying the genetic data from more than 240,000 people, scientists have found 538 genes which are linked to intelligence. …
Dr David Hill, of the University of Edinburgh’s Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE) who led the research, said: “Our study identified a large number of genes linked to intelligence. “We were also able to predict intelligence in another group using only their DNA.” …
But the new research suggests that intelligent people are biologically fitter.
In that they live longer, etc. Presumably, a lot of IQ variation is less due to having genes that are better, on paper, at generating higher IQ and instead are due to having fewer important genes that are broken due to unfortunate mutations (which may have negative consequences for both brain and body).
Here’s an analogy: a Jaguar is designed to have a higher maximum speed than a Toyota when everything is working right, but both cars’ speeds are zero when they are in the shop being fixed, and the Jaguar tends to be broken more.
The team also found that genes linked with problem-solving powers were associated with the process by which neurons carry signals from one place to another in the brain.
“We have shown is [sic] that two biological processes neurogenesis, the process by which new brain cells are created, and myelination of the central nervous system are associated with intelligence differences,” added Dr Hill.
I recall Ed Miller pointing to myelination back in the 1990s.
The study’s principal investigator, Professor Ian Deary, also from CCACE, said: “We know that environments and genes both contribute to the differences we observe in people’s intelligence. …
The research was published in the journal Molecular Psychiatry.
The full paper is here:
W. D. Hill, R. E. Marioni, O. Maghzian, S. J. Ritchie, S. P. Hagenaars, A. M. McIntosh, C. R. Gale, G. Davies & I. J. Deary
Molecular Psychiatry (2018)
11 January 2018
Intelligence, or general cognitive function, is phenotypically and genetically correlated with many traits, including a wide range of physical, and mental health variables. Education is strongly genetically correlated with intelligence (r g = 0.70). We used these findings as foundations for our use of a novel approach—multi-trait analysis of genome-wide association studies (MTAG; Turley et al. 2017)—to combine two large genome-wide association studies (GWASs) of education and intelligence, increasing statistical power and resulting in the largest GWAS of intelligence yet reported. Our study had four goals: first, to facilitate the discovery of new genetic loci associated with intelligence; second, to add to our understanding of the biology of intelligence differences; third, to examine whether combining genetically correlated traits in this way produces results consistent with the primary phenotype of intelligence; and, finally, to test how well this new meta-analytic data sample on intelligence predicts phenotypic intelligence in an independent sample. By combining datasets using MTAG, our functional sample size increased from 199,242 participants to 248,482. We found 187 independent loci associated with intelligence, implicating 538 genes, using both SNP-based and gene-based GWAS. We found evidence that neurogenesis and myelination—as well as genes expressed in the synapse, and those involved in the regulation of the nervous system—may explain some of the biological differences in intelligence. The results of our combined analysis demonstrated the same pattern of genetic correlations as those from previous GWASs of intelligence, providing support for the meta-analysis of these genetically-related phenotypes.