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Researchers Find Dozens of Genes Associated With Measures of Intelligence (arstechnica.com)
An anonymous reader quotes a report from Ars Technica: We don't know a lot about the biological basis of our mental abilities -- we can't even consistently agree on how best to test them -- but a few things seem clear. One is that performance on a number of standardized tests that purport to measure intelligence tends to correlate with outcomes we'd associate with intelligence, like educational achievement. A second is that this performance seems to have a large genetic component. But initial studies clearly indicated that the effect of any individual gene on intelligence is small. As a result, the first genetics studies found very little, since you needed to look at a large number of people in order to see these small effects. Now, a new study has combined much of the previous work and has turned up 40 new genetic regions associated with intelligence test scores. But again, the effect of any individual gene is pretty minor. The team behind the new work took advantage of open data to pull together information from 13 different studies, which cumulatively looked through the genomes of over 78,000 individuals. While those individuals had been given a variety of tests, the authors focused on measures of general intelligence or fluid intelligence (the two seem to measure similar things). The genomes of these individuals had been scanned for single base pair differences, allowing the authors to look for correlations between regions of the genome and test scores. Two separate analyses were done. The first simply looked at each base difference individually. That turned up 336 individual bases, which clustered into 22 different genes. Half of these had not been associated with intelligence previously. To provide a separate validation of these results, the authors did a similar analysis with educational achievement. They found that nearly all of the sites they identified also correlated with that. In a second analysis, the authors tracked base differences that cluster in a single gene. Since there are more markers for each gene, this tends to be a more sensitive way of looking for effects. And in fact, it produced 47 genes associated with the intelligence test scores. Seventeen of those had been identified in the earlier analysis, which brought the total genes identified to 52, only 12 of which had been previously associated with intelligence test scores.
statistical evidence that certain ethnic groups display on average higher intelligence than others (such as whites as compared to blacks).
IQ is not the same as intelligence, although it is almost certainly highly correlated.
Whites are not on top. Both Jews and East Asians score higher on average.
In America, blacks have mean IQ scores about 0.7 SD, or about 10 points, lower than whites.
Black children have, on average, twice the blood lead levels of white children.
The first large scale IQ testing in America was of recruits during the First World War, in 1917.
In those 1917 tests, the average score was 15 points below today's average.
A century ago, there was a 15 point gap in IQ scores between Protestant and Catholics in Ireland.
Today there is no gap.
So is the "IQ gap" caused by genetics? Maybe, but similar gaps in the past were not.
There is also a long ugly history of even scientists ignoring scientific findings that are socially unacceptable.
Different mean and standard deviation of intelligence found in groups of people defined through genetic locus controlling for education, culture, diet, and socioeconomic status is one of them.
The person that can prove four decades of scientific evidence wrong will be quite famous. Until then, everyone tries very hard to ignore the evidence and pretend it doesn't exist, as this paper did.
These results are from using SNP chips. To make a SNP chip, a sample of individuals from a population (in this case, humans of European descent) are sequenced, then the sequences are compared to find SNPs (single nucleotide polymorphism: i.e. a place where some individuals have one DNA base and others have a different one.) Then some hundreds of thousands of those SNPs are selected (we want something like an even spread of SNPs over the genome, and we want to chose SNPs which have a fairly high degree of polymorphism - we'd rather something which was 50:50 rather than 99:1.) A SNP chip is designed which when exposed to DNA from an individual will say yes/no for each SNP. (Scanning the paper, I see two of the SNP chips they used were UK BiLEVE Axiom array and the UK Biobank Axiom array which have over 820,000 SNPs each.)
This has several consequences. One is that the SNP chip is of limited use for populations other than the one for which it was designed. Another is that seldom is the SNP on the chip directly related to the feature/quality (intelligence in this case) that we are trying to correlate with. Rather, the SNP which correlates positively with IQ is probably just nearby the genetic difference which matters. Because they are close, recombination (shuffling of the two genome copies you have, which happens in the production of gametes) is unlikely to separate them. Because they will occasionally get separated, the correlation of IQ with the SNP is going to be a little less strong than the correlation of IQ with the actual variant gene (allele). A SNP chip is less informative than a full genome sequence, but is much cheaper, and much easier to analyse.
A final point is that genome wide association studies like this have in the past been plagued with false positives. When there are so many variables being tested (hundreds of thousands of SNPs on the SNP chip) some will strongly associate with your measured quality (IQ) by chance. This is even more so if you use sophisticated analyses which look for combinations of SNPs as predictors. I will provisionally accept that they've accounted for this correctly, as I lack the expertise to judge for myself.
I work in a tangentially associated field (phylogenetics) so my knowledge has some professional basis, but is well short of that of an expert in the field.
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ALL the genes put together had a total of 5% impact on Intelligence. That means an IQ of 105 vs 100. That is a minor effect.
Worst of all, minor effects like this, are typical of false positives. That is, most scientific tests use a significance threshold of no more than 4%, which is one in 25. That means if you test 25 different random alcoholic drinks, one of them, by random chance, will be shown to cause a minor increase in intelligence. This would be a false positive.)
And they did over 300 tests. So if they are using a 4% significance, that would be 4*3= 12 false positives.
This article looks like the worst kind of fake science news. You know, the kind that a President would quote (Pick Trump/Obama, whichever your personal bias thinks would do that).
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That doesn't seem like a good enough reason to put the kibosh on the study of intelligence. The racial angle is weak. Everyone that matters knows racial differences are small. But what we have to gain by learning about intelligence is huge. We can learn about learning disorders. We can try to ameliorate the damage of dementia. Granted that this also opens up a can of worms regarding what interventions are ethical, but that's not a racial issue.
The fact that something could--if you bend over backwards by ignoring the actual numbers--be used to promote racism shouldn't be a reason not to discuss it candidly when the context is bettering everybody's lives.
A cat can't teach a dog to bark.
But Jewish populations are genetically distinct, even between small sub-groups. As a whole they are farther from European clusters than many African, and of course are more closely related to Arabs from genetic drift measurements. Races are artificial and are scientifically meaningless; genetics is reality.