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Out of Africa's midlife crisis

razib.substack.com

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Re: Out of Africa's midlife crisis

#21

Post by bsanr2 »

fallingknife wrote: post #6
bsanr2 wrote: post #5

On an extremely tangential note: I wish we would stop using the term, "Sub-Saharan." The semantic quandaries should be obvious, but it also subscribes to a curious linguistic glitch of putting the North and South into a hierarchy that only exists if you are rather incurious about the ambiguity of geographic perspective (see: the infamous "upside down" Gall-Peters projection for some mind-blowey fun). I would personal…

Nobody in their right mind actually thinks placement towards the top of a map actually denotes some kind of hierarchy.

Orienting with terms like "top" and "bottom" inherently denotes hierarchy. Whether you ascribe meaning to that hierarchy (and I think people do) is another matter.

Explicitly stating direction rather than something that only refers to it with the aid of outside knowledge (the common orientation of maps) would be better. Otherwise, why don't we spin the map 180 degrees? Now the "correct" term would be "Super-Saharan Africa." Which is just as silly.

Re: Out of Africa's midlife crisis

#22

Post by dalbasal »

davisYC wrote: post #14
dalbasal wrote: post #8

For me, it's easier to understand these ideas by adopting a "lumper" mentality to human history. IE, Neanderthals, Denisovans, late Erectus & other archaics were just populations of humans. Sections on a large map of human diversity. On another section were, for example, that small subpopulation accounting for most modern human genetics. Near that little section were other subpopulations that even a "splitter" would…

i talk about introgression in this post https://razib.substack.com/p/here-be-humans the piece was not exhaustive and meant to be an intro

Cheers. These blogs are a treat.

Re: Out of Africa's midlife crisis

#23

Post by bsanr2 »

throwaway894345 wrote: post #12
bsanr2 wrote: post #5

On an extremely tangential note: I wish we would stop using the term, "Sub-Saharan." The semantic quandaries should be obvious, but it also subscribes to a curious linguistic glitch of putting the North and South into a hierarchy that only exists if you are rather incurious about the ambiguity of geographic perspective (see: the infamous "upside down" Gall-Peters projection for some mind-blowey fun). I would personal…

Putting aside the absurd nitpick on the "Sub-" prefix (everyone understands that this refers to "South" and not some position on a hierarchy). > (riffing on Asia Minor and referring to the fact that that part of the continent is, in fact, a majority of its landmass). Isn't Asia Minor a bit more than half of Turkey? It's certainly not a majority of all of Asia...

>Putting aside the absurd nitpick on the "Sub-" prefix (everyone understands that this refers to "South" and not some position on a hierarchy).

Is it absurd? Do they understand? Can you show me how you know this?

>Isn't Asia Minor a bit more than half of Turkey? It's certainly not a majority of all of Asia...

Sorry, I can see where I was unclear. I was referring to Africa.

Re: Out of Africa's midlife crisis

#24

Post by AlotOfReading »

davisYC wrote: post #18
dorfsmay wrote: post #15

Earlier quoted context omitted.

Do we have any idea about the size of the original population, the size of the group which left for Europe, the size of the group's who migrated to central/west Africa? I had heard that there were several waves of migration towards Europe, do we have a better estimate about this? Wouldn't multiple waves over time provide more diversity?

you can infer sizes from genetic diversity ('effective pop') for the out of africa group i've seen sizes from 100 to 10,000. i used 1,000 to 10,000 as a likely moderate number, and the range also points to the census size being larger we can assume that conditional on the size of OoA the other groups were way larger (10x or more). otoh, the main thing i did not explore is that i am now believing that africans themsel…

It's worth noting that effective population size != actual population size. The former is simply a lower bound on it. If the population is structured enough and in the right ways, the actual size can be orders of magnitude higher. This has been an issue with several supposed bottlenecks within African populations.

Re: Out of Africa's midlife crisis

#25

Post by fallingknife »

bsanr2 wrote: post #21
fallingknife wrote: post #6

Earlier quoted context omitted.

Nobody in their right mind actually thinks placement towards the top of a map actually denotes some kind of hierarchy.

Orienting with terms like "top" and "bottom" inherently denotes hierarchy. Whether you ascribe meaning to that hierarchy (and I think people do) is another matter. Explicitly stating direction rather than something that only refers to it with the aid of outside knowledge (the common orientation of maps) would be better. Otherwise, why don't we spin the map 180 degrees? Now the "correct" term would be "Super-Saharan A…

> and I think people do

Yes there do seem to be a lot of Eskimo supremacists around.

Re: Out of Africa's midlife crisis

#26

Post by valarauko »

nkurz wrote: post #4

I thought this was an interesting article. Summarizing from my very-non-expert POV, he's dividing the world into three groups: a small number (less than 1 million) original African inhabitants; a larger number (about a billion) sub-Saharan Africans who broke off about 100,000 years ago; and then the rest-of-the-world (who went though a tight bottleneck less than 100,000 years ago) about the time they left Africa. The…

> Did the the different tribes of African Bushmen start out as genetically distinct as they are today, or did they start from a common population and diverge over the last 200,000 years?

While groups like the San have a great deal of diversity within the group, they are also distinct from other Hunter Gatherer groups as well. The San are separated from the Hadza by about 110K years, IIRC.

> Were those who left Africa always distinct from those who stayed, or did they change through selection (and interbreeding with Neanderthals and Denisovans) over time?

Yes, those who left Africa were the remnants of a distinct population, separated from the ancestors of sub-Saharan Africans by 40K years when they left Africa 60Kya.

Re: Out of Africa's midlife crisis

#27

Post by nerfbatplz »

api wrote: post #11
fallingknife wrote: post #9

Earlier quoted context omitted.

Yes, everybody knows that, and if someone asks me where Greenland is on a map, I will say "at the top" like a normal person.

You don't reference the galactic orientation by reference to the nearest superclusters? Pleb.

The enemy's gate is down

Re: Out of Africa's midlife crisis

#28

Post by bsanr2 »

fallingknife wrote: post #25
bsanr2 wrote: post #21

Earlier quoted context omitted.

Orienting with terms like "top" and "bottom" inherently denotes hierarchy. Whether you ascribe meaning to that hierarchy (and I think people do) is another matter. Explicitly stating direction rather than something that only refers to it with the aid of outside knowledge (the common orientation of maps) would be better. Otherwise, why don't we spin the map 180 degrees? Now the "correct" term would be "Super-Saharan A…

> and I think people do Yes there do seem to be a lot of Eskimo supremacists around.

I'm not sure what this is supposed to mean.

Re: Out of Africa's midlife crisis

#29

Post by valarauko »

dalbasal wrote: post #20
valarauko wrote: post #13

Earlier quoted context omitted.

> No introgression with other Sapien populations? Perhaps indirectly. As he addresses later in the text, it's possible that Denisovans in South East Asia encountered Homo erectus and interbred with them. The Denisovans appear to have more population structure as compared to Neanderthals, and introgression from H. erectus might explain some of it. Considering that South East Asia and Papua New Guinea has the highest D…

Interesting. What I meant though was introgression with closer groups. IE there clearly were surviving populations that didn't go through the major sapien funnels. Their descendants are in the "very diverse" group. Obviously there was, is and will be "introgression" with them. Were there other such groups, in or out of sub-saharan africa... whos genes we carry?

I'm not sure what you mean by the other closer groups. My understanding of the field is that when anatomically modern humans expanded out of Africa for the first time 60Kya, they encountered Neanderthals and eventually Denisovans. What other "closer" group was out there for them to encounter?

The other anatomically modern humans were all in Africa, and it looks like there's been no interbreeding with them for at least 100K years. There has been a small introgression back into Africa by non-Africans within the last few thousand years, but that's a separate issue.

Re: Out of Africa's midlife crisis

#30

Post by selimthegrim »

bsanr2 wrote: post #5

On an extremely tangential note: I wish we would stop using the term, "Sub-Saharan." The semantic quandaries should be obvious, but it also subscribes to a curious linguistic glitch of putting the North and South into a hierarchy that only exists if you are rather incurious about the ambiguity of geographic perspective (see: the infamous "upside down" Gall-Peters projection for some mind-blowey fun). I would personal…

I’ve never heard anyone from the Indian subcontinent complain about this.
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