On the eastern affinities of Bacho Kiro IUP.

The recent re-excavations at Bacho Kiro cave (Bulgaria) by archaeologists from Bulgaria and Germany discovered remains of Homo sapiens dated to ~ 45/ 43,000 calBP (Hublin 2020). Three individuals from the Initial Upper Paleolithic layer and another one (a lovely lady) dating to ~ 37,000 calBP (~ Aurignacian era in Europe) were sequenced (Hajdinjak 2021).

Analysis showed affinity between the IUP horizon Bacho-Kirians (BK-IUP) and quasi-contemporaneous East Asian groups, e.g. the man from Tianyuan cave, China. And this was not the first time ‘eastern affinities’ were noted in Upper Paleolithic Europeans – such a signal had been previously noted in a ~ 35,000 year old sample from Goyet, Belgium (‘Goyet -Q116’) (Yang 2017). The shared affinities between Goyet and Tianyuan did not extend to later (partial) descendants of Goyet (such as El Miron) nor did the affinities involve more recent ancient or modern East Asians.

Were there populations movements from Eastern Asia into Europe, as some in the webosphere have suggested ? To be sure, a model of early (even pre-Toba) ‘southern coastal dispersals’ to the East have figured prominently in anthropological literature, and patterns inferred from modern DNA were suggested to support such a scenario.

However, with direct evidence from ancient DNA, the picture evolved. The paper by Hajdinjak et al found that IUP Bacho Kiro Cave individuals were related to populations that contributed ancestry to the Tianyuan individual in China as well as, to a lesser extent, to the GoyetQ116-1 and Ust’Ishim individuals (all |Z| < 3; Fig. 2d, Supplementary Information 6). This resolves the previously unclear relationship between the GoyetQ116-1 and Tianyuan individuals without the need for gene flow between these two geographically distant individuals. The cumulative evidence has also established that Upper Paleloithic populations in Europe and Siberia carried ‘East Asian’ lineages like Y-hg NO, C, F and mtDNA M, but these became increasingly attenuated by the Holocene.

From Hajdinjak – populations related to the IUP Bacho Kiro Cave individuals disappeared in western Eurasia without leaving a detectable genetic contribution to later populations, as indicated by the fact that later individuals, including BK1653 at Bacho Kiro Cave, were closer to present-day European populations than to present-day Asian populations.

Evidently, IUP diversity in Europe and western Siberia diminished and was supplanted by so-called West Eurasians (with some IUP-related ancestry preserved in the western Europe and Siberia in the East). Campanian ignimbrite ?

Marti 2016.

The below qpGraph provisionally explores affinities of early ancient Eurasian populations. Our understanding will continue to evolve with more data, however the basic structure of Out-of-African populations is becoming understood.

  1. Zlaty Kun +/- related groups
  2. A ‘West Eurasian’ cluster consisting of post-42 kyBP individuals from Europe and likely Western Asia, linked at least in part to the dispersal of Aurignacian, Ahmarian & related industries.
  3. The ‘IUP’ dispersal, which includes Ust-Ishim, BK-IUP, proto-ENA and a ”pre-Papuan” branch. To speculate, given the distribution of these populations, one wonders if it indeed is a relatively more eastern branch dispersing from ~ Central Asia.
Zwyns 2021

ADD: Brief sketch of putative dispersal paths ~ 45-40,000 bp, plus ANE 30-20,000 BP

References

Initial Upper Palaeolithic Homo sapiens from Bacho Kiro Cave, Bulgaria. Hublin et al 2020.

Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry. Hajdinjak et al 2021.

40,000-Year-Old Individual from Asia Provides Insight into Early Population Structure in Eurasia; Yang et al 2017

Genetics and material culture support repeated expansions into
Paleolithic Eurasia from a population hub out of Africa. Vallini et al; 2021

The Initial Upper Paleolithic in Central and East Asia: Blade Technology, Cultural Transmission, and Implications for Human Dispersals. N Zwyns 2021

Microliths in the South Asian rainforest ~45-40 ka: New insights from Fa-Hien Lena Cave, Sri Lanka. O Wedage et al 2021

Population increase and environmental deterioration correspond with microlithic innovations in South Asia ca. 35,000 years ago. Petraglia et al 2009.

Reconstructing the plinian and co-ignimbrite sources of large volcanic eruptions: A novel approach for the Campanian Ignimbrite. Marti et al 2016

7 thoughts on “On the eastern affinities of Bacho Kiro IUP.

  1. Interesting post but something I hadn’t noticed before regarding Yang et al (2017).
    “Using D(EUR<14 kya, Kostenki14/GoyetQ116–1, TY, EAS) (Table S3C), we show that EAS share more alleles with EUR<14 kya than the Tianyuan individual shares with them, relative to Kostenki14 and GoyetQ116–1, further supporting connections between EAS and ANE, the VWE, Karelia and Motala12. We note that EAS also share a connection to Satsurblia, Stuttgart, and the French and Sardinian, indicating other potential interactions unrelated to ANE or VWE."

    This is very curious, perhaps I am misunderstanding something but does it not suggest gene flow between East Asians and Europeans post 14kya? Then would what you say here "The shared affinities between Goyet and Tianyuan did not extend to later (partial) descendants of Goyet (such as El Miron) nor did the affinities involve more recent ancient or modern East Asians." be wrong?

    1. Hi Andy. Yes, the ‘East Asian’ affinities only reached central-western Europe after 14,000 calBP, however I understand them to be very ancient. Specifically, they are more likely related to a Central Asian population before it moved into East Asia ~ 40 kyBP, and were mediated via Siberian-related ANE groups which arrived to eastern Europe at a yet to be specified time (forming EHG), and then indirectly reached west-central Europe.
      Before 14,000 bp, C-W Europe was populated by ‘Magdalenian’ populations. It is the ‘Villabruna’ (Epigravettian-related) populations which are thought to have links with ANE, and such ancestry diffused through C-W Europe with post-Magdalenian Azilians & the like.
      ANE -related groups appear to have also made a significant impact in parts of West Asia during the Epipalelithic (esp. Iran_Neo, CHG) via pathways independent of EHG.

      1. Thank you for the response!

        So just to make sure I understand you, you are suggesting that the “East Asian but not Tianyuan” affinity in WHGs (and in my understanding also in Iran_Neo and CHG since you mentioned them) is due to older East Asian-related ancestry that did not arrive in Europe independently but mediated by ANE?

        For the sake of discussion, I have two questions/objections about this that I’d appreciate your thoughts about:

        1) If it was an older gene flow event would it not be more related to populations like Ust’ishim or Tianyuan? It instead appears very “East Asian-like” (I think Yang used Han and Ami as proxy).

        2) There was recently a very weird paper about Oceania by Murchi et al. “Genomic insights into population history and biological adaptation in Oceania” that suggested that there was a Denisovan introgression event into East Asians about 21kya and that it then reached West Eurasian populations via a younger than 20kya East Asian gene flow into Europe. At the same time, in his view East Asians have very recent Negrito-like introgression which introduced another type of Denisovan ancestry into East Asia. What would your thoughts be about that inference? (personally I am puzzled due to the lack of both archaeological and uniparental evidence for this)

        Contradicting the above, in the more recent publication “Denisovans and Homo sapiens on the Tibetan Plateau: dispersals and adaptations” the inferred East Asian-specific Denisovan introgression event was older than 40kya, in which case agreeing with what you said above. The Mal’ta boy did have some Denisovan introgression after all if I am not mistaken.

        No idea what to make of the above in all honesty, papers contradict each other frequently after all.

  2. It’s risky making deductions using modern populations, and would depend which other moderns were used or not. I would say qpGraph is more robust because it is constrained by multiple affinities of populations used. It is possible some later East Asian admixture is also present, however – as you say- it is not evident in any uniparental markers or other historical explanations. The first time such admixture becomes manifest in Europe seems to be with the Huns

    I’ve added a quick illustration to place an image to the graph.

    1. That is a neat illustration, so if I am understanding this and Yang’s paper correctly, the reason later East Asian affinities in Europe are not Goyet-driven or MA1-driven is because the ANE that arrived in Europe had some old Central Asian “East Asian-like” affinity but more than MA1 had (the ENA1 node in your graph) ?

      I am skeptical of the recent date of Denisovan introgression and then later gene flow presented in that model but since it coincides with the inferred admixture date (East Asians show affinities to post but not pre-LGM Europeans) I was wondering if it had anything to do with it. But it seems a trend to use archaic introgression to constrain admixture events, to perhaps more limited utility than suggested in the related papers (esp when dealing with such low amounts of archaic admixture and lack of ancient DNA).

      1. I think using archaic introgression is useful, but some of the methods are novel, which is why they appear to show different conclusions. A better sample set of archaic might be useful in future.
        I agree that during the Late Paleolithic there is ENA admixture diffusing West, but that is distinctive to that during the Early Paleolithic. What that needs is close analysis of Yana, MA-1, Afonotova-Gora3

  3. Only now noticed the reply, yes I agree with all your points albeit what would do you mean by differential ENA diffusions between early and late Paleolithic? Technically, all ANE samples recovered thus far fit into the Late Paleolithic.

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