When Thor Heyerdahl came up with the theory in 1947 that Easter Island and other Polynesian islands were once visited by Native Americans from South America, the scientific establishment laughed him off. But now an extensive genetic study reveals that Heyerdahl was partly right. THE DNA comparisons show that there must have been contacts between the Polynesians and pre-Columbian indigenous American people centuries before the appearance of the Europeans. Visitors from South America left their genes in the Polynesian population.

For decades, researchers have been arguing about where the first settlers of Easter Island and the islands of Polynesia to the west came from, and whether or not there were influences from South America. According to common wisdom, the roots of these islanders lie on the Asian mainland and the Philippines. Thanks to favorable winds, they were able to travel long distances on the Pacific with their boom boats and double hull canoes, thus reaching Polynesia in the eleventh and twelfth centuries.

Recent genetic studies supported this origin of Polynesians. But there are archaeological and linguistic features that also suggest early contact with South America – this was already noticed by the Norwegian explorer and adventurer Thor Heyerdahl. The stone figures of Easter Island and other statues of Polynesia are similar to those of some Central American cultures. In addition, the sweet potato native to South America can also be found on the islands of the South Seas. “Even the Polynesian word for sweet potato is similar to the term from languages from the Andes,” explains first author Alexander Ioannidis of Stanford University.

Native American DNA in the genetic material of Polynesians

So far, however, neither archaeological nor genetic studies have been able to resolve the controversy surrounding the possible connection between Polynesian and pre-Columbian native Americans. Two earlier comparisons of DNA from the bones of long-dead indigenous people of Easter Island with South American populations yielded contrasting results – partly because the old DNA was too fragmented and thus only partially comparable. Ioannidis and his colleagues have therefore taken a different approach. They collected DNA samples from 807 study participants from 17 Polynesian islands and 15 Native American peoples along the Pacific coast of South America. In the genomes, they then used special statistical analysis methods to search for sequences that are characteristic of the respective populations. This allowed them to determine if and when there were crossbreeding and mixing of the different populations.

The evaluation initially revealed, as expected, that a large part of today’s inhabitants of Polynesia carry DNA markers of both Europeans and various South American Native American tribes in the genetic material. These genes were introduced when Europeans began colonizing these islands at the beginning of the 19th century, and also brought with them workers from South America. But on the easternmost islands of Polynesia, including Easter Island, the scientists found another admixture in the genetic material: they were DNA sequences typical of the Zapoteks and Mixe peoples native to Mexico and the Zenu natives living in Colombia. “This Central American component of the Rapa Nui is not linked to either European or other South American gene markers,” Ioannidis and his team report. This suggests that these genes came to Easter Island independently of European colonization.

First contact back in the Middle Ages

Through further analysis, the researchers were able to narrow down when these contacts must have occurred between Polynesians and Central Americans. “This mixture happened long before the arrival of the Europeans,” the scientists say. Thus, as Thor Heyerdahl suspected, there were indeed early contacts between native American sailors from South America and the inhabitants of the Polynesian islands.

According to the calculations, the earliest contact between The natives and Polynesians took place around 1150 on the island of Fatu Hiva, which belongs to the southern Marquesas. This fits with studies showing that this archipelago was the easiest to reach from South America due to ocean currents and winds. “The date for this first contact is close to the date for the first settlement of this archipelago determined by radiocarbon dating and raises the exciting possibility that the Polynesian settlers already encountered a small, already established population of Native Americans upon arrival on these islands,” Ioannidis and his colleagues explain.

However, the opposite scenario is not excluded: some Polynesian sailors may have reached the north of South America and then returned to their islands with Indian companions. The genetic data also show that the remaining islands of eastern Polynesia and also Easter Island were probably settled from the Marquesas. “The descendants from this first mixture then brought their double heritage to the new islands, and the later trade between the islands may also have played a role,” the researchers said. Easter Island was the last to be settled by the Polynesians with Native American genit. Thus it seems clear that Heyerdahl correctly suspected, at least in part, that there was early contact between South America and Polynesia.

Arthur Marquis

Marquis was born in Paris, France and emigrated to United States at the early age of 5. He gained a medical degree from the University of Michigan and has worked as a dermatologist for over 10 years. He covers a wide-range of health related subjects for the Scientific Origin.