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Maciamo
22-07-20, 14:25
A new paper confirms that Native pre-Columbian Americans from Colombia migrated to Eastern Polynesia 800 years ago and intermingled with the expanding Polynesian population of Austronesian origin.

Native American gene flow into Polynesia predating Easter Island settlement, Ioannidis et al. (2020) (https://www.nature.com/articles/s41586-020-2487-2)

Abstract

The possibility of voyaging contact between prehistoric Polynesian and Native American populations has long intrigued researchers. Proponents have pointed to the existence of New World crops, such as the sweet potato and bottle gourd, in the Polynesian archaeological record, but nowhere else outside the pre-Columbian Americas, while critics have argued that these botanical dispersals need not have been human mediated. The Norwegian explorer Thor Heyerdahl controversially suggested that prehistoric South American populations had an important role in the settlement of east Polynesia and particularly of Easter Island (Rapa Nui). Several limited molecular genetic studies have reached opposing conclusions, and the possibility continues to be as hotly contested today as it was when first suggested. Here we analyse genome-wide variation in individuals from islands across Polynesia for signs of Native American admixture, analysing 807 individuals from 17 island populations and 15 Pacific coast Native American groups. We find conclusive evidence for prehistoric contact of Polynesian individuals with Native American individuals (around AD 1200) contemporaneous with the settlement of remote Oceania. Our analyses suggest strongly that a single contact event occurred in eastern Polynesia, before the settlement of Rapa Nui, between Polynesian individuals and a Native American group most closely related to the indigenous inhabitants of present-day Colombia.

Nature Reviews Genetics: An odyssey to Oceania (https://www.nature.com/articles/s41576-020-0271-7)

"In addition to a large Polynesian component, many islanders harboured genomic regions of European ancestries, likely resulting from colonial admixture. Strikingly, the four easternmost Polynesian islands (Palliser, Marquesas, Mangareva and Rapa Nui) showed two ancestry components characteristic of both modern and ancient central and southern Native American populations.

The central Native American component, characteristic of Indigenous Mexican and Indigenous Colombian individuals, was found to be associated only with the Polynesian component using compositional analysis. This finding suggests that it arrived independently of any European component. Moreover, little variation of the central Native American component across different Rapanui individuals is suggestive of an older admixture event, before the arrival of Europeans in the Pacific region."
[...]
"Finally, by modelling the length distribution of the Polynesian, Native American and European ancestry segments in Pacific islanders, the team was able to infer an initial Native American–Polynesian admixture event dating to around AD 1200, predating the settlement of Rapa Nui. The date estimate was confirmed using a linkage disequilibrium-based dating method."

Eochaidh
22-07-20, 14:39
Here is the link to Thor Heyerdahl's book "American Indians In The Pacific" from 1952. This is not the familiar paperback entitled "Kon Tiki", but a 700 page research document.
It is hosted on Archive.org and available in the usual formats. https://archive.org/details/AmericanIndiansPacificHeyerdahl/mode/2up

ihype02
22-07-20, 18:26
That's impressive.

Tamakore
27-01-21, 11:34
It's strange that an academic paper would cite Thor Heyerdahl as an authority. To quote from his Wikipedia page:

"This [Odin] project generated harsh criticism and accusations of pseudoscience from historians, archaeologists and linguists in Norway, who accused Heyerdahl of selective use of sources, and a basic lack of scientific methodology in his work...The controversy surrounding the Search for Odin project was in many ways typical of the relationship between Heyerdahl and the academic community. His theories rarely won any scientific acceptance, whereas Heyerdahl himself rejected all scientific criticism and concentrated on publishing his theories in popular books aimed at the general public."

Can we expect renewed support for his theories that ancient Egyptians crossed the Atlantic on papyrus boats or that Norwegian culture originated in Azerbaijan?

Heyerdahl believed that Polynesia was first settled from South America, and that's what his Kon Tiki expedition was trying to prove. This latest study, which is based entirely on the DNA of modern populations, seems to start with the assumption that any admixture between Polynesians and South Americans before 1492 must be the result of South Americans sailing Kon Tiki-like across the Pacific to East Polynesia. There is no evidence of South Americans making long distance voyages across the Pacific, whereas there is a mountain of evidence that Polynesians did have the necessary sailing vessels and navigational techniques to make such long distance voyages, including return voyages.

If there was a single admixture event between Polynesians and South Americans around 1200, the most likely explanation is that Polynesians sailed to South America and then returned to Polynesia after some inter-marriage. How likely is it that, after 15,000 years, South Americans would happen to start making voyages into Remote Oceania and finding tiny islands at the very time that Polynesians were discovering and settling the previously uninhabited islands of East Polynesia?