DNA Study Finds No Evidence that Ancient Easter Islanders Intermixed with South Americans

A new study of ancient DNA appears to rule out the likelihood that inhabitants of Easter Island intermixed with Native South Americans prior to the arrival of Europeans on the island in 1722.

Fehren-Schmitz et al found no Native American admixture in pre- and post-European-contact Rapanui. Image credit: Bjørn Christian Tørrissen / CC BY-SA 3.0.

Easter Island (also known as Rapa Nui), a remote island in the southeast Pacific Ocean, has long been a source of intrigue and mystery.

How did such a small community of people build so many impressively large statues? And what happened to cause that community to collapse?

Researchers have also been curious about what kind of contact native Easter Island inhabitants, known as Rapanui, might have had with South Americans prior to the arrival of Europeans.

Earlier genetic evidence seemed to support early contact between the Rapanui and Native South Americans.

But the new study, reported in Current Biology, calls those findings back into question.

“We found no evidence of gene flow between the inhabitants of Easter Island and South America,” said lead author Dr. Lars Fehren-Schmitz, from the University of California, Santa Cruz.

“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.”

Ancestry proportions of the ancient Rapanui samples when compared to the reference population dataset. Image credit: Fehren-Schmitz et al, doi: 10.1016/j.cub.2017.09.029.

Dr. Fehren-Schmitz and colleagues analyzed bone fragments from the ancient skeletal remains of five Rapanui that were excavated in the 1980s and became part of the Kon-Tiki Museum’s collection in Oslo, Norway. Three individuals lived prior to European contact, and two lived after.

“DNA, including both complete mitochondrial genomes and low-coverage autosomal genomes, indicates that the DNA of the sampled individuals falls within the genetic diversity of present-day and ancient Polynesians,” the authors said.

“We can reject the hypothesis that any of these individuals had substantial Native American ancestry,” Dr. Fehren-Schmitz added.

“Our data suggest that the Native American ancestry in contemporary Easter Islanders was not present on the island prior to European contact and may thus be due to events in more recent history.”

According to the team, slavery, whaling, mass deportations, and other activities that followed European contact gave rise to opportunities for intermixing that likely left the genetic imprint seen in islanders today.

“The most likely scenario is that there wasn’t a single episode. Acknowledging that his results answer one question but leave many others unanswered. The story is simply more complicated than we expected,” Dr. Fehren-Schmitz said.

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Lars Fehren-Schmitz et al. Genetic Ancestry of Rapanui before and after European Contact. Current Biology, published online October 12, 2017; doi: 10.1016/j.cub.2017.09.029