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In 1947, an expedition led by the Norwegian explorer, Thor Heyerdahl sailed from the coast of Peru on a wooden raft called “Kon-Tiki” to prove a bold theory. Heyerdahl was convinced that people from South america could have reached the islands of Polynesia already in pre-columbian times. The crew sailed for 101 days in a trip of 7,000 miles to reach the islands of the Pacific, demonstrating that the idea was not at all far-fetched. In this way, Heyerdahl challenged the hypothesis most accepted at the time, which meant that the remote area of the world had been populated only by travelers from Asia. Despite his achievement, his theories were criticized by most experts.
Now, an international team of researchers may have finally put an end to this dispute, giving the reason to Heyerdahl, thanks to a wide genetic study that have collected DNA data of more than 800 indigenous people living in America and French Polynesia. For the first time, scientists have found genetic signatures common to reveal the contact between the two peoples before the arrival of europeans to South america. That encounter could happen only once, around the year 1200 d.C. in the eastern Polynesia between the islanders and a group closely related to the indians of the present coast of Colombia . The new study, published this week in the journal “Nature”, shows that Easter Island was not the first point of contact, as has been suggested in some previous reports.
sweet potato DNA –
The possibility of contacts prehistoric between polynesians and native americans has been much debated. One of the arguments in their defence has been a tuber: the sweet potato. This plant of american origin has a long history of cultivation in eastern Polynesia. In addition, the word sweet potato in the languages polynesian seems to be related to the word used by the indigenous people of the Andes. On Easter Island there is evidence of former fields of sweet potatoes and other evidence of cultural exchange: the extraordinary masonry of the ancient and a specific cult to the bird man, all features in common with south America.
Moai Statues on the site of Rano Raraku on Easter Island – Javier-White
Some researchers have turned to the genetics of the sweet potato, with the hope of demonstrating that the potatoes domesticated in South America, and Polynesia were genetically the same. But have not managed to confirm the propagation mediated by the human being. Other studies have analyzed ancient DNA from bones belonging to native americans and polynesians. The ancient samples often degrade, so these studies were also not able to provide sufficient evidence that the two populations shared a moment of history.
In general, the detractors of these meetings have considered all this evidence inconclusive, stating that it was only conjecture, and that the two groups were separated by thousands of miles of open ocean.
But the new study goes far beyond, to be the first to provide strong evidence for genetic. The researchers visited the indigenous communities to explain their purposes, and assess interest in participation, and seek consent. Then, they collected saliva samples from 807 participants in 17 polynesian islands, and 15 native american groups along the Pacific coast of the Americas from Mexico to Chile, conducting genetic analyses to search for DNA fragments that are characteristic of each population and segments that are identical by descent, which means that are inherited from the same ancestor many generations.
“we Found segments identical-by-descent native american in several polynesian islands,” says Alexander Ioannidis, postdoctoral researcher at Stanford University and co-principal of the study. “It was a conclusive evidence that there was a single event of contact shared,” he says. In other words, the polynesians and the native americans they met in a moment of history, and during that time the people of the two cultures had children with his DNA.
Meeting in the Marquesas of the South
The statistical analysis confirmed that the event occurred in the Middle Ages, around the year 1200 d.C., that is “around the time that these islands were originally settled by polynesian natives”, notes Ioannidis. Using computational methods, the team located the source of the DNA of native americans in modern-day Colombia.
genomic Studies above have focused on the contact on the Easter Island, because it is the polynesian island inhabited closest to South America. However, the new study supports the idea that the first contact was in one of the archipelagos of east Polynesia (such as the Marquesas of the South), as proposed by Thor Heyerdahl. These findings suggest that the contact occurred earlier than previously thought and spread across multiple islands in Polynesia, suggesting that the native americans had a genetic influence and culture in Polynesia for more than five centuries before the arrival of europeans to the region.
“If you think about how the story for this period of time, it is almost always a history of european conquest, and you never hear really of all the others,” he reasons Ioannidis. “I think that our work helps to tell these untold stories, which is really exciting.”