Source: TW
Over the past several thousand years, alleles that increase intelligence have become more common in Europeans, due to natural selection. So Europeans today are considerably smarter than their ancestors were 10,000 years ago. These frequency changes only involved a few hundred alleles at most, a small fraction of the genome. So they don’t have much effect on whole-genome stats like Fst.
विस्तारः (द्रष्टुं नोद्यम्)
FST, or the fixation index, is a measure used in population genetics to quantify the degree of genetic differentiation between populations. It essentially tells us how much genetic variation exists between groups compared to the total variation within and between them. The term comes from Sewall Wright’s F-statistics, and FST is a specific case of those metrics.
Lewontin used to argue that human populations aren’t that different in overall gene frequencies ( Fst is not that big), so they couldn’t be really different. Of course they really are different in skin color, so why couldn’t they be really different in anything else?
They can !
Skin color differences are caused by changes in the frequency of the narrow (< 1%) set of alleles that influence skin color . Correlated differences: the pale-favoring ones increased. Had almost no effect on overall genetic stats like Fst.
Substitute “intelligence” for “skin color”:
Intelligence differences are caused by changes in the frequency of the narrow (< 1%) set of alleles that influence intelligence . Correlated differences: the smart-favoring ones increased. Had almost no effect on overall genetic stats like Fst.
Several of the alleles affecting skin color have large effects: largest is SLC24a5. After that’s there’s a long tail with much smaller effect sizes.
With intelligence, just the long tail.