Three years ago, a genetic study of the people of Easter Island reported that they had acquired distinctively South American DNA. Although the majority of their heritage was Polynesian, the research indicated some interaction with the peoples of the neighboring continent before Europeans arrived. Science, however, is always evolving, and new research found an absence of distinctively South American DNA from before the 18th century – a rather puzzling discovery.

Mark Twain famously said; “It was wonderful to find America, but it would have been more wonderful to miss it.” Yet, it seems almost as if this is what the inhabitants of Easter Island did. Having crossed the Pacific to find the tiny dot originally known as Rapa Nui, Polynesian navigators don't seem to have gone on to trade with the continent beyond. If they did, there was no interbreeding to leave a mark in the Easter Islanders' DNA.

The previous work that identified South American inheritance among Easter Islanders was based on the genetics of the island's modern inhabitants. However, while statistical methods proposed that interaction with the South Americans happened centuries ago, an alternative explanation suggests it was more recent – around the time when Europeans colonized the island, possibly importing slaves.

Dr Lars Fehren-Schmitz, of the University of California Santa Cruz, extracted DNA from the bones of five skeletons dug up on Easter Island in the 1980s, reporting his findings in Current Biology. Three of the individuals predated European arrival in 1722, while two lived later.

"We found no evidence of gene flow between the inhabitants of Easter Island and South America," said Fehren-Schmitz in a statement. "We were really surprised we didn't find anything. There's a lot of evidence that seems plausible, so we were convinced we would find direct evidence of pre-European contact with South America, but it wasn't there."

Although Easter Island is thought to have never supported more than 18,000 people, the civilization there was once wealthy enough to carve and transport the nearly 1,000 giant statues that make the island famous. Such surplus, combined with an astonishing sea-faring heritage, might be expected to drive the inhabitants to South America to trade. Indeed, some theories propose they did so in sufficient numbers for Polynesians to have made a second settlement in the Americas.

The presence of sweet potatoes, which originated in the Americas, in Polynesian farming centuries ago, was seen as evidence that these early explorers returned to their homelands with the products of their journeys. Yet if this occurred, the history of human migrations predicts that some South Americans would have come back too, leaving descendants among the Polynesians, something contradicted by Fehren-Schmitz's work.