From a new paper (PDF) released yesterday:
GENETIC CONSEQUENCES OF SOCIAL STRATIFICATION IN GREAT BRITAIN
Human DNA varies across geographic regions, with most variation observed so far reflecting distant ancestry differences. Here, we investigate the geographic clustering of genetic variants that influence complex traits and disease risk in a sample of ~450,000 individuals from Great Britain. Out of 30 traits analyzed, 16 show significant geographic clustering at the genetic level after controlling for ancestry, likely reflecting recent migration driven by socio-economic status (SES). Alleles associated with educational attainment (EA) show most clustering, with EA-decreasing alleles clustering in lower SES areas such as coal mining areas. Individuals that leave coal mining areas carry more EA-increasing alleles on average than the rest of Great Britain. In addition, we leveraged the geographic clustering of complex trait variation to further disentangle regional differences in socio-economic and cultural outcomes through genome-wide association studies on publicly available regional measures, namely coal mining, religiousness, 1970/2015 general election outcomes, and Brexit referendum results.
In other words, even leaving aside immigrants, scientists can see that English people who migrate out of coal towns like Rotherham for the bright lights of the metropolis tend to have higher polygenic scores for educational attainment (i.e., years of education) than English people who stay home in dead end coal towns. Of course, a simpler way to do this would be just to ask people what their years of educational attainment are, but it’s kind of cool that you can get to a similar result by looking at their DNA.
Once you have some proof of concept studies like this, it might be possible to move on to tests where the answers are more up in the air at present. For example, Dalton Conley wants to test Richard Herrnstein’s famous 1972 theory that in the past in America there was less assortative mating on IQ than after the college testing revolution. One way to do it is look at the DNA of old people or of dead people and estimate their IQ (or a correlate like educational attainment) from that and see if they married less assortatively than young people.
I look forward to testing Herrnstein’s thesis because, while it seems obvious on logical grounds, it would be nice to know for sure. After all, Herrnstein wasn’t really that familiar with the Old America, so he was just making up a plausible story. Social history can be complicated.
Conley’s first try a half decade ago using very early polygenic scores didn’t find much support for Herrnstein’s theory, but now polygenic scores are based on much larger sample sizes, so his rather brilliant brainstorm is now more practicable.