Early American DNA in Rapa Nui islanders suggests Polynesians visited Americas

Evidence that Polynesians visited the Americas has been intriguing, if controversial, but new genetic studies of Rapa Nui (Easter Island) natives seem to confirm it.

Results of thorough genetic studies on 27 Rapa Nui natives reveal the presence of South American DNA that showed up 19 to 23 generations ago. That takes it back to 1280 to 1495, before Europeans were in the Pacific. 

There is European DNA there, too, but it showed up much later, in the 1800s. Rapa Nui wasn’t discovered by Europeans until the Dutch voyager Jacob Roggeveen visited on Easter of 1722. 

This new genetic work adds to other evidence: The presence of American sweet potatoes and possibly American bottle gourds throughout the Pacific, and the presence of Polynesian chicken DNA at El Arenal in Chile. RaisingIslands covered the Polynesian chicken research here. 

 The new genetic evidence, published in the 23 October issueof Current Biology, seems to lock up once and for all the mystery: Is it possible that Polynesians, having discovered every single habitable island in the tropical and subtropical Pacific, could have missed the American continent?

The authors of the paper, entitled Genome-wide Ancestry Patterns in Rapanui Suggest Pre-European Admixture with Native Americans, write:

“We generated genome-wide data for 27 Rapanui. We found a mostly Polynesian ancestry among Rapanui and detected genome-wide patterns consistent with Native American and European admixture. By considering the distribution of local ancestry tracts of eight unrelated Rapanui, we found statistical support for Native American admixture dating to AD 1280–1495 and European admixture dating to AD 1850–1895,” the authors wrote.

“These genetic results can be explained by one or more pre-European trans-Pacific contacts,” they said. 

The paper was written by a dozen scholars: J. Víctor Moreno-Mayar, Simon Rasmussen, Andaine Seguin-Orlando, Morten Rasmussen, Mason Liang, Siri Tennebø Flåm, Benedicte Alexandra Lie, Gregor Duncan Gilfillan, Rasmus Nielsen, Erik Thorsby, Eske Willerslev, and Anna-Sapfo Malaspinas.

It is theoretically possible that the American genes got there from South American sailors making the voyage to Rapa Nui, but since Polynesians have a famous voyaging and navigation culture and South Americans did not, it seems unlikely. 

This sets up interesting speculations. Polynesians are believed to have reached Rapa Nui about 1200 AD. Was it members of that same initial voyaging group that went on to visit the South American coast and then return? Or did Polynesian navigation continue between the Eastern Pacific islands and South America for generations after the initial Rapa Nui visit.

There’s a lot of stuff happening in the first few centuries of the millennium in Eastern Polynesia. Sweet potato showed up in the Pacific around 1000 AD. Rapa Nui folks arrived at an uninhabited Rapa Nui about 1200. South American genes got into the Rapa Nui gene pool between 1280 and 1495.  The El Arenal chicken bones were dated at 1321 to 1407.

It was all going on during the period when Polynesian cultures were known to be actively voyaging across the Pacific. It may be a stretch, but it seems that this new genetic data suggests not a single accidental voyage to the Americas, but a series of voyages, in which at a minimum:

            -- Sweet potatoes were collected in the Americas and delivered into the Pacific.

            -- Polynesian moa (chickens) were delivered from the Islands to the American Coast.

            -- And there was some genetic mixing. Did a Polynesian sailor bring home a mate, or did 

 Polynesians stay long enough to have children and bring them home, or did a couple of venturesome South American natives join the Polynesian canoe for the trip to Rapa Nui?

Here is Science Daily’s story on the paper. 

As a side note, the evidence is also another piece of evidence for the quality of Polynesian navigation. Unlike many of the islands in the Pacific, Rapa Nui is a loner. It is small, and not part of a chain of islands like Hawaii, Tahiti, the Marquesas, Samoa and so forth. Those would be easier to find since they’re a much bigger target--you just have to find the archipelago.

But Polynesian navigators appear to have found tiny Rapa Nui repeatedly, and from both the east and the west. That is a prodigious navigational feat.

© Jan TenBruggencate 2014

Citation: J. Víctor Moreno-Mayar, Simon Rasmussen, Andaine Seguin-Orlando, Morten Rasmussen, Mason Liang, Siri Tennebø Flåm, Benedicte Alexandra Lie, Gregor Duncan Gilfillan, Rasmus Nielsen, Erik Thorsby, Eske Willerslev, Anna-Sapfo Malaspinas. Genome-wide Ancestry Patterns in Rapanui Suggest Pre-European Admixture with Native Americans. Current Biology, 2014 DOI: 10.1016/j.cub.2014.09.057