A very interesting paper by the controversial Shi Huang, published in 2017 (On the peopling of the Americas: molecular evidence for the Paleoamerican and the Solutrean models. Dejian Yuan, Shi Huang. bioRxiv 130989; doi: https://doi.org/10.1101/130989).
Shi proposed the Maximum Genetic Diversity (MGD) theory to explain evolution and how species diversify. It addresses the concerns raised by the "molecular clock" and also concepts like "junk DNA", "neutral mutations", epigenetic effects, etc.
In this paper he looks into the origin of Native Americans, and does so with his "Out of Asia" outlook.
Shi suggests an old date, earlier than currently accepted, and even hints at the feasibility of Neanderthals entering America before modern humans!
"The timing of first entry into America by humans remains to be estimated by future DNA studies. Several human sites in America, including the Topper site in South Carolina United States, the Burnham site in Oklahoma United States, sites in Brazil and Chile, suggest that humans were in the New world as early as 30,000 years ago to perhaps 60,000 56. This old age for the first settlement is consistent with the findings here that ancient Amerindians had more ancestry from Southern Chinese (Hunan) relative to Northern Chinese (Fujian), the recent finding of modern humans originating in South East Asia, and the African or Australo-Melanesian like genome in Paleoamericans or Native Americans that could only have come from Neanderthals (30). Also compatible with results here is the recent discovery of a ∼130000 year old human site in North America (60), indicating that admixture of Neanderthals and modern humans might have happened in America, which appears to be the more likely model given the absence of Amerindian mtDNA C1, C4c and D1 haplotypes in North East Asia and Siberia that shared more informative alleles with Neanderthals than their respective sister haplotypes in North East Asia and Siberia (30). If Neanderthals were present in North East Asia and Siberia, there seems a priori no reason that they could not find their way through the Bering Strait."
The paper he cites as "(30)" is: Yuan, D. et al. Modern human origins: multiregional evolution of autosomes and East Asia origin of Y and mtDNA. bioRxiv, doi: https://doi.org/10.1101/106864 (2017).Google Scholar, where Shi is a coauthor.
This paper has boldly proclaims in its abstract "We found evidence of modern Y and mtDNA originating in East Asia and dispersing via hybridization with archaic humans. Analyses of autosomes, Y and mtDNA all suggest that Denisovan and Neanderthal were archaic Africans with Eurasian admixtures and ancestors of South Asia Negritos and Aboriginal Australians. Verifying our model, we found more ancestry of Southern Chinese from Hunan in Africans relative to other East Asian groups examined. These results suggest multiregional evolution of autosomes and replacements of archaic Y and mtDNA by modern ones originating in East Asia, thereby leading to a coherent account of modern human origins."
I must confess that I find the arguments rather vague, and some explanation regarding "slow" and "fast" SNPs would come in handy. I am no expert in this field and I guess most scholars don't consider his maximum genetic diversity (MGD) hypothesis seriously. The authors could have added more context to interpret their findings, which to them seem obvious, but not to me. Shi's X (Twitter) profile has a link to the MGD website, where he explains how it works (and includes a list with all of his publications).
Nevertheless, I do give them credit for this paper that boldly goes against the current prevailing consensus and pushes against the Out Of Africa hypothesis with strong arguments.
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