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Thread: "Craniometrics Reveal “Two Layers” of Prehistoric Human Dispersal in Eastern Eurasia"

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    "Craniometrics Reveal “Two Layers” of Prehistoric Human Dispersal in Eastern Eurasia"

    https://www.nature.com/articles/s41598-018-35426-z

    This new paper got some press this week. From an adna perspective, huge dataset of craniometric measurements of Siberian, East Asian and Sahul populations.... but the scenario they present of separate dispersal of proto-East Asians into Siberia from West Eurasia, then isolated for 41kya there(!) is flatly contradicted by ancient dna showing much more recent arrival from the south of fairly fully formed East Asian ancestry (https://www.biorxiv.org/content/10.1101/448829v1 - "The first inhabitants, a previously unknown population of "Ancient North Siberians" (ANS), represented by Yana RHS, diverged ~38 kya from Western Eurasians, soon after the latter split from East Asians. Between 20 and 11 kya, the ANS population was largely replaced by peoples with ancestry from East Asia, giving rise to ancestral Native Americans and "Ancient Paleosiberians" (AP), represented by a 9.8 kya skeleton from Kolyma River. Between 11 and 4 kya, AP were in turn largely replaced by another group of peoples with ancestry from East Asia, the "Neosiberians" from which many contemporary Siberians derive.")

    All that Siberian cranial dataset is from that post 20kya and even largely post 11kya expansion... The perils of trying to estimate ancient continuity given massive post-glacial replacement, followed by ongoing late Holocene expansion...

    They suggest alternatively: "In terms of the deeper origins of the apparently homogenous NEA population, we may consider the more ancient homelands and migratory routes, prior to the entrance into the Yellow and Yangtze River areas by 9 kya but potentially much earlier. In one possible scenario, ancient people perhaps of the “first layer” with Australo-Papuan features moved into Siberia and subsequently adapted to the extremely cold climate during the Last Glacial Maximum (LGM) of 24– 16 kya.". But that seems a bit strange again in the light of the results from the Yana paper (even when East Asian related ancestry emerges in Siberia at Kolyma at 8000 BCE and then outside Siberia at Devil's Gate at 5000 BCE, there's not much indication that the early Kolyma like groups back-migrated south again, as there's a lack of their Ancient Siberian related ancestry).

    Another thing I wanted to comment on is the absence of pre-neolithic material from North China plain, and northern precincts generally. Does that reflect a real absence of existing material (prior to the neolithic HG just weren't living there) or a sampling gap?

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    Craniometrics definitely seems hit-or-miss when it comes to inferring actual population history when cross-validated against actual genomic data. I guess a topical example would be the genomic analysis that was recently done on this Upper Paleolithic Mongolian skullcap: http://www.ox.ac.uk/news/2019-01-30-...t-found-region

    Prior to the sequencing, many suspected this was an archaic hominid of some kind based on the morphology of the calvarium, and I can definitely see why - very prominent brow ridges with a very low skull and almost no forehead. Although to be fair, I think so far they've only been able to extract mtDNA from the skull, so if they're ever able to get a whole genome sequence out of it, this specimen might still end up having a significant proportion of archaic ancestry that could explain the unusual features it exhibits relative to modern humans.

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    Quote Originally Posted by Eterne View Post
    But that seems a bit strange again in the light of the results from the Yana paper (even when East Asian related ancestry emerges in Siberia at Kolyma at 8000 BCE and then outside Siberia at Devil's Gate at 5000 BCE, there's not much indication that the early Kolyma like groups back-migrated south again, as there's a lack of their Ancient Siberian related ancestry).

    Another thing I wanted to comment on is the absence of pre-neolithic material from North China plain, and northern precincts generally. Does that reflect a real absence of existing material (prior to the neolithic HG just weren't living there) or a sampling gap?
    Yana is not everything. The first Siberian genome is Ust Ishim 45 kya and it is more related to modern East Asians than West Eurasians but it seems to precede East-West separation. Tianyuan is also interesting. It is related to Goyet in Europe and Ust Ishim. Yana is 15 kya younger than Ust Ishim.

    The lack of any ancient autosomal data from China (apart from Tianyuan) is a great pity.

    The tree diagram from the Dzudzuana paper is interesting, but we have to keep in mind that it lacks Onge-like reference.

    Dzudzuana suppl fig S3_6.GIFDzudzuana suppl fig S3_6.GIF
    Last edited by Kristiina; 02-25-2019 at 03:56 PM.

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    @Kristiina, you're correct Ust Ishim is really important to our understanding, but to say that Yana isn't everything in Siberia because of him is a bit like saying Kostenki and all post Aurignacian Europeans aren't everything in Europe because of Oase1. UI has no certain contribution to any later population at this point (no real evidence for it, and some evidence against it in the general equal relatedness of later post-Basal populations).

    (Though in the supplements to Sikora 2018, Ust Ishim does actually have his highest formal stats with Yana, funnily enough, so if his pop contributed to anyone sampled so far, it's probably Ancient North Siberians and Ancient North Eurasians, as would seem most probable.)

    There were surely phylogenetically ENA populations who contributed to both East Asians and also increasingly to later Ancient North Eurasians through time though. Just not much sign so far of what the authors here posit; an early split between their "two layers" leading to East Asians and all other ENA, where one layer migrated through Central Asia and was resident in NE Siberia for upwards of 40000 years. Instead the latest inhabitants of Siberia from the late LGM onwards and mid-Holocene look like arrivals from somewhere within the broader East Asian region, and inference from modern samples is misleading the authors of this cranial study.

    The phylogenetic position of Dzudzuana is going to be important as well, like you say.

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    Quote Originally Posted by Eterne View Post
    UI has no certain contribution to any later population at this point (no real evidence for it, and some evidence against it in the general equal relatedness of later post-Basal populations).
    It is the same with Yana, Sikora et al could not make Yana to contribute to modern populations. We know from the uniparental data that there is no yDNA P(xQ) or mtDNA U2’3’4’7’8 in Northeast Asia or America.

    Sikora et al suppl fig S6_10.GIF
    Last edited by Kristiina; 02-25-2019 at 10:41 AM.

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    Quote Originally Posted by Eterne View Post
    Just not much sign so far of what the authors here posit; an early split between their "two layers" leading to East Asians and all other ENA, where one layer migrated through Central Asia and was resident in NE Siberia for upwards of 40000 years. Instead the latest inhabitants of Siberia from the late LGM onwards and mid-Holocene look like arrivals from somewhere within the broader East Asian region, and inference from modern samples is misleading the authors of this cranial study.
    In addition to this new paper, we have the following:

    Uniparental markers: K2a (Ust Ishim) and K2b (Yana, Malta) and mtDNA R (Ust Ishim), Tianyuan (R/В), Yana (R/U2’3’4’7’8), Malta (R/U*) in Siberia and northern East Asia.

    Classical genetic markers: Computer simulation of human leukocyte antigen genes supports two
    main routes of colonization by human populations in East Asia
    Computer simulation of human leukocyte antigen genes and colonization of East Asia.GIF

    https://www.google.fi/url?sa=t&rct=j...pKxLzmZvg2DCvV

    Male Demography in East Asia: A North–South Contrast in Human Population Expansion Times
    "We have investigated male demography in East Asia, applying a Bayesian full-likelihood analysis to data from 988 men representing 27 populations from China, Mongolia, Korea, and Japan typed with 45 binary and 16 STR markers from the Y chromosome. According to our analysis, the northern populations examined all started to expand in number between 34 (18–68) and 22 (12–39) thousand years ago (KYA), before the last glacial maximum at 21–18 KYA, while the southern populations all started to expand between 18 (6–47) and 12 (1–45) KYA, but then grew faster. We suggest that the northern populations expanded earlier because they could exploit the abundant megafauna of the “Mammoth Steppe,” while the southern populations could increase in number only when a warmer and more stable climate led to more plentiful plant resources such as tubers."

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1456369/
    Last edited by Kristiina; 02-25-2019 at 12:47 PM.

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    Zhoukoudian is only about 10 km from Tianyuan Cave. Though the date of the Upper Cave occupation is uncertain (this paper says 34-10 ka BP) the most recent study I found says minimally 35.1-33.5 ka, which would put these samples not too far from Tianyuan in time as well.

    I don't remember what the phylogenetic position of Tianyuan is (or if that was ever really sorted out). Can the Northeast Asian cranial type be a specialization of a more generalized Australasian type?

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    @Kristiin: No, but Yana is a closely related clade to populations which do, across Siberia until the early post-glacial and then mid-Holocene replacement. Ust Ishim does not seem to form a clade with anyone else we can detect (and certainly not any present day East Asian or Siberian population).

    Yana and its clade don't contribute to modern populations in Siberia much because of <20kya expansions and possibly extinctions due to climate. Ust Ishim may not because of post-Ust Ishim, pre-Yana expansions of ANS for the same reason.

    On the other points, respectfully of your knowledge here, I don't really believe think y-str from 2006 or HLA from 2015 on sets of modern populations are going to find anything much different than autosomal and cranial dna on the same sets of population failed to find, and I guess I've discussed the reasons why they failed to find what actually happened. Routes that go over Mal'ta and Afontova Gora near Baikal as in those maps don't really work for East Asia, because the people who we samples of living there don't form a clade with them. That is, however much they analyse it, the available set of modern data only includes truly massive expansions and replacements from the south, not anyone actually representative of people who lived there 20-11 kya, and not really even of people who lived there pre-11 kya to a great extent.

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    I am interested in hard data.

    Whatever we propose, we have to take into account the K2 node of the yfull tree.

    yfull K2.GIF

    Yana P is slightly younger than the TMRCA of P, while Ust Ishim K2a is slightly older than the TMRCA of K2a on yfull. K2a and K2b formed 45400 years ago, which is more or less the age of Ust Ishim.

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