The ancient Polynesian peoples who lived on Easter Island, 1,100 miles from the closest land, weren't as isolated as has long been believed, genetic studies have shown.
The ancient people living on the island, also known as Rapa Nui, had substantial contact with several Native American populations centuries before the first Westerners arrived at the island in 1722, scientists say.
People may have been making voyages from Easter Island to the Americas well before the 18th century, as genome analysis of 27 native Rapanui people confirms significant contact between the island people and Native Americans somewhere between AD 1300 and AD 1500, researchers report in the journal Current Biology.
Best known for the 900 giant statues of stone heads known as moai created on Easter Island, the Rapa Nui culture flourished beginning around AD 1200 until it began to decline by the 1500s.
However, genetic data suggests interbreeding between Rapa Nui people and native peoples living in South American had been taking place, possible as early as the 1300s.
"We found evidence of gene flow between this population and Native American populations, suggesting an ancient ocean migration route between Polynesia and the Americas," says geneticist and study leader Anna-Sapfo Malaspinas of the Center for GeoGenetics at the University of Copenhagen.
The genetic data cannot determine whether Rapa Nui people journeyed to South America or Native Americans voyaged to Easter Island, experts say, although they lean toward the Rapa Nui people as most likely to have made the dangerous round trips across the Pacific.
Easter Island Polynesians probably voyaged to South America to swap goods to obtain chickens, sweet potatoes or other food sources, and brought South American women back with them, they say.
"It seems most likely that they voyaged from Rapa Nui to South America and brought South Americans back to Rapa Nui and admixed with them," said Mark Stoneking, a geneticist with Germany's Max Planck Institute for Evolutionary Anthropology. "So it will be interesting to see if in further studies any signal of Polynesian, Rapa Nui ancestry can be found in South Americans."
Intermixing with Native American people likely occurred between 19 and 23 generations ago, while European genes entered the Rapa Nui genome much later, probably in the 19th century, the researchers said.
The genetic lineage of Rapa Nui people today is about 75 percent Polynesian, 10 percent Native American and 15 percent European.