On the edge of Africa and Eurasia

[Jovialis]

Here is an interesting blog post by Razib Khan on Insitome.

And Arabia may not simply have been a transit point. The latest ancient genetic work suggests that the humans who left Africa were separated into two primary ones. One population did not mix with the Neanderthals to the north and east. While another group did. This second group became the ancestors of all the humans today found in Europe, Asia, Oceania, and the New World. The first group seems to have remained close to Africa and mixed eventually with the first group, giving rise to the various peoples of West Asia and North Africa.

https://blog.insito.me/on-the-edge-...npsg14i93Wx9mUo2UFYaST0zECIap2tYtdDQctZ7tcDqs

 

[bicicleur 2]

'The first group seems to have remained close to Africa'

wrong :

there is plenty of evidence of presence modern humans in Sahul and SW China prior to the date of Neanderthal admixture (50-55 ka)

 

[Megalophias]

I think he means Basal Eurasians as part of the main Out of Africa wave (whether or not this is accurate), not the much earlier Out of Africa wave who may have left their own small but distinct ancestral signature in Australian Aborigines.

 

[Ygorcs]

'The first group seems to have remained close to Africa'

wrong :

there is plenty of evidence of presence modern humans in Sahul and SW China prior to the date of Neanderthal admixture (50-55 ka)

Well, those earlier waves of unadmixed humans may have simply died out and become totally replaced (or perhaps absorbed as a tiny minority in the eventual gene pool) outside the Middle East/Southwest Asia when the later waves expanded throughout Eurasia and to Oceania via Sahul.

 

[bicicleur 2]

Well, those earlier waves of unadmixed humans may have simply died out and become totally replaced (or perhaps absorbed as a tiny minority in the eventual gene pool) outside the Middle East/Southwest Asia when the later waves expanded throughout Eurasia and to Oceania via Sahul.

yes, maybe, but I think they were the origin of the Basal Eurasian

 

[bicicleur 2]

I think he means Basal Eurasians as part of the main Out of Africa wave (whether or not this is accurate), not the much earlier Out of Africa wave who may have left their own small but distinct ancestral signature in Australian Aborigines.

the earliest Basal Eurasian we have is from Dzudzuana cave 26 ka
we don't know where it came from, we only know it didn't come from Europe or Siberia

 

[markod]

yes, maybe, but I think they were the origin of the Basal Eurasian

I think there's no excess of Basal Eurasian ancestry in the south-eastern part of Eurasia. To the contrary, many populations there have eleveated Neanderthal ancestry compared to other Eurasians.

 

[halfalp]

I think there's no excess of Basal Eurasian ancestry in the south-eastern part of Eurasia. To the contrary, many populations there have eleveated Neanderthal ancestry compared to other Eurasians.

I'm confused, do Southeastern Asians have Neanderthal ancestry too or is it Denisova ancestry? I remember some paper that labeled Denisova ancestry as " Altai Neanderthal ". So i'm a little bit confused.

 

[thejkhan]

Do the Negritos, Papuans, Aus Aborigines have any Neanderthal ancestry at all? They seem very different from other Eurasians. Would make more sense if they come from an earlier wave out of Africa that encountered different archaic hominins.

 

[Ygorcs]

I'm confused, do Southeastern Asians have Neanderthal ancestry too or is it Denisova ancestry? I remember some paper that labeled Denisova ancestry as " Altai Neanderthal ". So i'm a little bit confused.

I think East Eurasians as a whole have both Neanderthal and Denisovan ancestry.

 

[Ygorcs]

the earliest Basal Eurasian we have is from Dzudzuana cave 26 ka
we don't know where it came from, we only know it didn't come from Europe or Siberia

Yes, but already heavily mixed with non-BE admixtures. I think we can only say that BE people, if they existed, probably admixed into the non-BE majority pretty early, maybe even before 30 ka.

 

[bicicleur 2]

Yes, but already heavily mixed with non-BE admixtures. I think we can only say that BE people, if they existed, probably admixed into the non-BE majority pretty early, maybe even before 30 ka.

it is pretty straightforward : DzuDzuana is a mixture of 72 % WHG-like with 28 % Basal Eurasian
and then there is Taforalt which has some 'ancestral north african' added to this mixture

 

[ThirdTerm]

Arabia may not simply have been a transit point. The latest ancient genetic work suggests that the humans who left Africa were separated into two primary ones.

One population did not mix with the Neanderthals to the north and east. While another group did.

His blog post does not specify the source but Razib Khan may have referred to "Homo sapiens in Arabia by 85,000 years ago" by Groucutt et al. (2018), which was published in Nature Ecology & Evolution. A Homo sapiens finger bone at least 85,000 years old was unearthed by the team led by Michael Petraglia at the Max Plank Institute for Science of Human History. Petraglia argues that the movement of modern humans out of Africa was not a single rapid movement 60,000 years ago but there were multiple dispersals out of Africa such as a route that cuts through the Arabian Peninsula. Razib Khan argues that this group of H. sapiens in the Arabian Peninsula stayed there and they didn't migrate any further to the Levant and beyond, where another group of modern humans interbred with the Neanderthals. Arabia holds the key to understanding the human expansion to the rest of the world.

Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130–90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60–50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95–86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall.

 

[halfalp]

I think East Eurasians as a whole have both Neanderthal and Denisovan ancestry.

I remember the paper that said that East Asians had more Neanderthal ancestry than West Eurasians. But how many exactly? I dont think as far as i remember that East Asians had any Denisovan ancestry, only Oceanians had some. So what about Southeast Asians?

 

[bicicleur 2]

I think there's no excess of Basal Eurasian ancestry in the south-eastern part of Eurasia. To the contrary, many populations there have eleveated Neanderthal ancestry compared to other Eurasians.

my guess is not SE Asia, it is the Indus delta and coastal Gujarat, areas that now are submerged by the sea
at the time there was an interesting habitat of mangrove forests and probably good fishing opportunitiesin these areas, a bit like Sundaland

 

[bicicleur 2]

His blog post does not specify the source but Razib Khan may have referred to "Homo sapiens in Arabia by 85,000 years ago" by Groucutt et al. (2018), which was published in Nature Ecology & Evolution. A Homo sapiens finger bone at least 85,000 years old was unearthed by the team led by Michael Petraglia at the Max Plank Institute for Science of Human History. Petraglia argues that the movement of modern humans out of Africa was not a single rapid movement 60,000 years ago but there were multiple dispersals out of Africa such as a route that cuts through the Arabian Peninsula. Razib Khan argues that this group of H. sapiens in the Arabian Peninsula stayed there and they didn't migrate any further to the Levant and beyond, where another group of modern humans interbred with the Neanderthals. Arabia holds the key to understanding the human expansion to the rest of the world.

there are many indications of modern humans in southern Asia prior to 60 ka apart from this 85 ka finger bone
but the DNA they left in todays population is marginal, as all Eurasians have the 55-50 ka Neandertahl 2 % DNA from somewere in SE Asia

 

[bigblob]

East Asians interbred with 2 different groups of Denisovan:

https://www.the-scientist.com/the-n...nisovans-from-two-different-populations-29948

 

[thejkhan]

I remember the paper that said that East Asians had more Neanderthal ancestry than West Eurasians. But how many exactly? I dont think as far as i remember that East Asians had any Denisovan ancestry, only Oceanians had some. So what about Southeast Asians?

East Asians have 20% more Neanderthal ancestry than Europeans. South East Asians though have less Neanderthal ancestry than Europeans.