Reading about European genetics and the Neanderthal genome and how we’re all related, just to a matter of degrees - sister; cousins; extended family; ethnicity; rest of humanity etc.
Since it’s obvious who the closest related people on Earth are, who are the most unrelated, genetically speaking? A South American Indian and Kalahari Bushman? Australian Aborigine and Greenlander Iniut? Any educated (or otherwise) guesses?
Nonsense. Both of those groups are part of the main extra-African migration. They are far more closely related than any two randomly selected African groups.
In short form, everyone who left Africa is very closely related to everyone else who left Africa. So the the most unrelated groups are going to include at least one African population.
There have been geneticdistanceanalyses that gives a very rough idea of degree of relatedness. But note that it is very rough.
Firstly, genetic distance isn’t a direct measure of degree of relatedness by any means, just a rough approximation. Founder effects, bottlenecks and selection pressures can result in very big genetic distances between very closely related populations. That’s compounded because the genetic distances are calculated based on just a few DNA sequences.
But the degree of consistency of these studies with different sub-populations, different sequences and different sample sizes allows a fair degree of confidence in the results. Based on these, the least closely related people are southern/western Africans, probably Bushmen or Pygmies at one extreme, and one of the isolated terminal populations at the other, either South American Indians or Australian Aboriginals.
That’s also consistent with what we understand about human migrations. Those human populations that remained near the point of our origin have of course retained the highest diversity and must include one end of any genetic trail. And those populations that have spread the furthest from home and had the least mixing with other populations are most likely to have passed through bottlenecks and been exposed to unique selection pressures to produce the most divergence from the original population.
The San are, of course, very closely related to the Khoi-Khoi. In fact they are essentially the same people with different social organisations and have been intermarrying for thousands of years prior to which they were the exact same people. They are also, of course, very closely related to the Bantu peoples with whom they have been intermarrying for centuries.
The Wikipedia link only notes that the San have relatively high frequencies of divergent Y-chromome and mitochondrial DNA. It never suggests that the San are equally distantly related to every other human being, as you claim.
Of course not. Humans have only been in South America for ~ten thousand years
And I guess I overstated the case with the San. In the early 90’s they were saying it was certain Pygmy groups. I thought they were now saying the San, but I guess it’s more complicated. Still, the point remains that there are groups within Africa that are more distinct from each other than they are from any non-African.
You can be forgiven for that; it can be very hard for researchers collecting samples in the field distinguish between groups, which leads to confusion in the literature. Nonetheless, there are certain characteristics that help. For example, San people always ride single file to hide their numbers.
Coolbeans. I have sometimes used the example of African and Australian Aboriginal groups to argue against strictly genetic interpretations of “race”, since I knew that “racially black” Africans are less closely related to “racially black” Aboriginals than they are to many “racially white” populations.
But I never realized that some “racially black” Africans and “racially black” Aboriginals might actually be, in genetic terms, the least closely related human populations on the planet!
But wouldn’t Norwegians and Aboriginals be equally distantly related to the Pygmies? The Norwegians and Aboriginals share a common ancestor with each other that is more recent than the most recent common ancestor shared with Pygmies. It’s meaningless to say that an Aboriginal or a Norwegian or a Native American is more or less related to the Pygmy: they’re line split from the Pygmies first, and then later diversified as they spread over the globe. I guess you could make some sort of genetic argument if one of them experienced more of a bottleneck than another, but from a cladistic standpoint (not really the right word when describing diversification within a single species, but whatever), they are exactly equally related (barring more recent intermarriage, which again, given that we’re all the same species, does happen to some extent)
What you’re overlooking is that human populations aren’t isolated and never have been. The larger separation between Aboriginals and San represents less gene flow between those populations, not the date of separation.
For example, large numbers of Norse ended up in large numbers in Slavic areas of Poland. The Vandals from Poland had previously ended up in large numbers ended up in North Africa. Berbers from North Africa ended up in large number in Nigeria. And Bantu people from Nigeria currently make up ~80% of the population in what was once San territory.
And that’s just the migrations that we know of that have occurred in large numbers in the past 2, 000 years. There would have been many more in the past 40, 000 years since the ancestors of the Aborigines and Norwegians left Africa. As a result, it’s likely that any individual San shares at least one ancestor with any individual Norwegian in the past 200 generations.
In contrast, once people reached Australia, they became more-or-less isolated. There was some contact with the outside world, but no large scale migrations. Most interbreeding with outsiders was one way, with Aboriginal women bearing children to foreign men on Australian soil. And the limited gene flow that did run outwards moved very slowly and in small numbers. Maybe two Timorese each generations had an Australian ancestor. And maybe a hundred Javanese had Timorese ancestry and so forth through the whole SE Asian chain and through Malaya and India. There was just no large scale migration outwards from Australia to Southern Africa, and certainly no rapid, long distance migration equivalent to the movement of the Vandals into Egypt in a few generations, or the movement of the Bantu into Botswana in a few generations. As a result, Australians are much less closely related to Africans than Norwegians are.
So the last common ancestor of *every *Norwegian and *every *Aboriginal is probably ~40, 000 years ago. And the last common *every *Norwegian and every *every *San is probably ~60, 000 years ago. And the last common *every *Aboriginal and every *every *San is also probably ~60, 00 years ago.
But the last common ancestor of *any random *Norwegian and *any random *Aboriginal is probably ~30, 000 years ago. And the last common *any random *Norwegian and every *any random *San is probably ~10, 000 years ago. And the last common *any random *Aboriginal and every *any random *San is probably ~50, 000 years ago.
So while the split between Norse and San and Aboriginals and San is at the same time, the backflow rate has produced a much higher degree of relatedness.
Eyeballing the 3-D depictions (based on the three most principal components), the Hadza and Pygmies are very distinct from each other, within Africa. But the distance between Africans and non-Africans is also large.
According to that figure, Native Americans to Hadza appear to be the two groups which answer OP’s question. (The paper’s dataset included a few Australians, but no Andamanese.)
In very simplistic terms, humans spent hundreds of thousands of years distributing and differentiating themselves across Africa (with all the genetic variation that would imply).
Then, a small (probably genetically similar) selection spread across the rest of the world.
The upshot is that humans have spent less time outside of Africa than they have within it.
Depending on the exact dates and the population that exited Africa you may well expect the greatest differences to exist within Africa itself.
This is a bizarre post. In what way are “African Negroes” a group, other than geographically and in a really old-fashioned racist view of the world? Where do you think the South Pacific Islanders came from, space?