Easter Island is the most remote place humans have ever colonized, and the fact we got there at all is a miracle. Now it looks like this island was colonized not once, not twice, but three entirely separate times.
The first and most important wave of colonization was by Polynesians, who probably reached the island sometime between 700 and 1,100 C.E. The third and final wave were the Europeans, who first encountered the island in 1722 and returned in the 1860s for a series of devastating raids that sold much of the indigenous population into slavery. There's now genetic evidence to suggest another colonization of Easter Island in between these two: specifically, by the peoples of South America.
The idea that ancient Americans had a hand in colonizing Easter Island is not new. The legendary (and controversial) adventurer archaeologist Thor Heyerdahl was convinced that the roots of Easter Island were in South America, not Polynesia, a conclusion he reached based on supposed similarities between the famous head statues on Easter Island and monuments from ancient Bolivia.
To prove ancient Americans could have reached Easter Island, he undertook the famous Kon-Tiki voyage, in which he sailed a raft all the way from Peru to Polynesia, using materials similar to those that would have been available to ancient Americans. The trip made international headlines, but it was at best circumstantial evidence. Later, more rigorously scientific research proved fairly definitively that Easter Island was primarily, if not exclusively, settled by Polynesians.
But that might be about to change. University of Oslo researcher Erik Thorsby has collated blood samples he collected from Easter Islanders in 1971 and 2008. The specific people he dealt with had no history of interbreeding with Europeans or other non-indigenous visitors to the island, meaning their bloodlines were effectively the same as those who lived on the island before European contact.
Thorsby examined the HLA genes, which are useful for revealing the geographic origins of one's ancestors. Most of the islanders involved in the study had HLA genes that showed obvious Polynesian heritage, but a select few also carried HLA genes that are only known in Native American populations.
Since those who carried these HLA genes came from the same extended family, Thorsby was able to trace the probable first carrier of these unusual genes. Her name was Maria Aquila, and she was born in 1846, more than a decade before European slave traders showed up and started interbreeding. That means, in all likelihood, that the Native American visitors who brought these HLA genes to the island arrived before the Europeans.
But how long before? What's interesting is that the Polynesian and American HLA genes have started to blend together, a process known as recombination. That takes a long time to happen, and Thorsby suspects the influx of American genes must have happened before Dutch explorer Jacob Roggeveen visited the island in 1722.
This doesn't mean that Heyerdahl was right - he's still pretty massively wrong - but Thorsby says this means he wasn't completely wrong about an ancient American presence on Easter Island. The only question now is how these genes got there. It's possible that Native Americans did undertake a voyage to Easter Island much like Heyerdahl's Kon-Tiki expedition.
The more likely possibility, based on the cultures' respective maritime technologies, is that Easter Islanders sailed on eastward to Chile, then returned with Native Americans colonists. Whether they made that journey willingly is lost to history. Either way, we can consider this another scrap of evidence in favor of the idea that Polynesians and Americans made contact long before Columbus.