Basal Eurasian discussion

[kolompar]

Short video: 
https://www.youtube.com/watch?v=vXOyVG-LNoA

I'm skeptical of these methods I don't understand
Here is the paper:
https://www.science.org/doi/10.1126/sciadv.aax5097
So it's only West Africans which is plausible as other methods also indicated it. They have CSFS for other populations too in the supplements so we can check out how much it makes sense.

The Z score for Natufian is lower simply because less SNPs, less certain result. The f4 estimates itself look correct. But what's going on in South Africa?
I find it much less likely that OoA humans stopped and contemplated for thousands of years in Eurasia. I think they must have had some huge technological advantage that allowed them to overtake other humans very quickly, and the conditions for OoA were a short, rare one-off event.

The linked pnas paper (graph is shown below) mentions that OoA occurs at about 80kya, followed by "Arabian Standstill". This clearly requires the back migration of E and D2 (D0) into Africa, and if it is true, we may see the genetic adaptation/related alleles in Africans significantly. So then it may become conflictive. Anyway, a single OoA without back migration is more parsimonious.

However, if a single OoA occured at 50kya (even not 55-60kya), there would be no time left for the genetic adaptation mentioned in the paper. So, either there is a bias in the research of the paper, or the ages of CT, DE, and D may be older than expected. I remember that some studies and graphs suggest that the ages of DE (Yap) and D (CTS3946 level) may reach 73-71 kya, and if the initial OoA population size is smaller, then 10,000 to 20,000 years may be enough for the "Arabian Standstill".

Finally, I believe that the replacement of Neanderthals and Denisovans was largely due to the diseases carried by the OoA population. It is known to all that the migration route of Oceanians is through South Asia and Southeast Asia, but the entire southern route region lacks IUP tools. Southeast Asia and Southern China maintain the ancient pebble-tool industry.

I'm not convinced by that paper at all, not sure if they can even detect the sweeps well. Just look at fig 1, looks very European biased and even there the variation is so large (unless I'm misunderstanding what it's showing). Then even if they got that right there's no reason it would all be OoA adaptation and even less reason it would be during an Arabian standstill, that's just what they wanted to see into it. There could have been selection already in a separated population back in Africa, and I feel like the OoA bottleneck itself could also show as such a hard sweep.

This study may be relevant for your discussion:

https://www.nature.com/articles/s41467-024-46161-7

The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal

    Leonardo Vallini, Carlo Zampieri, Mohamed Javad Shoaee, Eugenio Bortolini, Giulia Marciani, Serena Aneli, Telmo Pievani, Stefano Benazzi, Alberto Barausse, Massimo Mezzavilla, Michael D. Petraglia & Luca Pagani

Nature Communications volume 15, Article number: 1882 (2024)

Abstract

A combination of evidence, based on genetic, fossil and archaeological findings, indicates that Homo sapiens spread out of Africa between ~70-60 thousand years ago (kya). However, it appears that once outside of Africa, human populations did not expand across all of Eurasia until ~45 kya. The geographic whereabouts of these early settlers in the timeframe between ~70-60 to 45 kya has been difficult to reconcile. Here we combine genetic evidence and palaeoecological models to infer the geographic location that acted as the Hub for our species during the early phases of colonisation of Eurasia. Leveraging on available genomic evidence we show that populations from the Persian Plateau carry an ancestry component that closely matches the population that settled the Hub outside Africa. With the paleoclimatic data available to date, we built ecological models showing that the Persian Plateau was suitable for human occupation and that it could sustain a larger population compared to other West Asian regions, strengthening this claim.

Note: there are no new data in this paper, they analyze already published data.

Nice of them to try to contribute to the thread but I don't think derived allele sharing with Tianyuan/Kostenki is a particularly informative model in 2024. I guess we can celebrate the 10 year anniversary of their publication but for scientists it might be a good idea to reconsider it and look for something new? The paleoclimate data looks interesting though.