View Full Version : Eastern Polynesia colonised by Austronesians and Native Americans

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)


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."

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

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