Here’s an un-peer reviewed new preprint from researchers at Duke and Princeton:
by Alejandro Ochoa, John D. Storey
This article is a preprint and has not been peer-reviewed
Kinship coefficients and FST, which measure genetic relatedness and the overall population structure, respectively, have important biomedical applications. However, existing estimators are only accurate under restrictive conditions that most natural population structures do not satisfy. We recently derived new kinship and FST estimators for arbitrary population structures. Our estimates on human datasets reveal a complex population structure driven by founder effects due to dispersal from Africa and admixture. Notably, our new approach estimates larger FST values of 26% for native worldwide human populations and 23% for admixed Hispanic individuals, whereas the existing approach estimates 9.8% and 2.6%, respectively. While previous work correctly measured FST between subpopulation pairs, our generalized FST measures genetic distances among all individuals and their most recent common ancestor (MRCA) population, revealing that genetic differentiation is greater than previously appreciated. This analysis demonstrates that estimating kinship and FST under more realistic assumptions is important for modern population genetic analysis.
It’s been quite a few years since I thought about the math of the Richard Lewontin controversy over human genetic diversity, so I’d appreciate it if commenters better informed than myself took a crack at interpreting the numbers.
Here’s my understanding of the background. Please let me know if I’m getting this wrong.
Many decades ago, Richard Lewontin pointed out that the majority of the genetic diversity within the human species is not allotted along the lines of race and sub-race.
You can get a hint of this just by comparing fraternal twins to identical twins. Fraternal twins are usually moderately different in looks, personality, athletic abilities, IQ, and so forth, while identical twins are clearly much less genetically diverse.
Even within the most racially homogeneous community, people differ a lot in personality, intelligence, size, etc etc.
Similarly, you can notice two people of different races who are fairly similar in important ways. For instance, Baseball Reference calculates similarities between the career statistics of baseball players and other players. Here are the 10 most similar batters to the Angels’ Mike Trout, a white superstar:
- Frank Robinson (955.4) *
- Ken Griffey Jr. (940.0) *
- Mickey Mantle (935.5) *
- Hank Aaron (909.7) *
- Miguel Cabrera (896.6)
- Orlando Cepeda (877.8) *
- Mel Ott (877.3) *
- Eddie Mathews (866.2) *
- Andruw Jones (863.5)
- Albert Pujols (858.8)
Trout is most often compared to Mickey Mantle, another white superstar, but this calculation sees him as even more similar in performance to two black greats, the late Frank Robinson and Ken Griffey Jr.
Obviously, performance is not exactly equal to genotype, but it probably has some relationship.
So, a lot of the genetic diversity among humans is fairly random, rather than reflecting racial differences.
If I recall correctly, Lewontin estimated based on the early technology of his day that only 15% of genetic diversity in the human species was allocated according to racial and subracial ancestry.
This estimate is often used by the more sophisticated proponents of the Race Does Not Genetically Exist dogma. What they are really saying is, well, okay, race does exist genetically, but only to minor extent: the racial/subracial genetic diversity glass is 85% empty and only 15% full.
The late genetic anthropologist Henry Harpending told me about 20 years ago that he thought Lewontin was being overly-generous and the real number should be even lower: 12.5%
Frank Salter and Harpending then pointed out in the early 2000s, however, that that 12.5% diversity figure is actually quite important: 12.5%, using Sewall Wright’s way of calculating relatedness, is the average figure for, say, an uncle and his nephew. So, say, Scotsmen, relative to Vietnamese, are about as similar to other Scotsmen as a Scot uncle is to his Scot nephew relative to other Scots.
That’s not huge but it’s not insignificant either.
But now these new researchers, with access to giant amounts of data, are suggesting that genetic differences among racial populations have been underestimated. I haven’t read the paper yet, and I’m out of practice at interpreting these numbers, so let me leave it at that for now.