The fascinating and remote Rapa Nui or Te Pito o Te Henua, also known as Easter Island, sits almost 2,000 kilometers (1,242 miles) from the nearest Polynesian island and is 3,700 km (2,299 mi) west of South America. Its unique features have led researchers including archaeologists and geneticists to study and debate the history of the island and its people. One point of contention is whether Polynesians who lived on the island long ago made contact with indigenous South Americans before they first met European colonizers in 1722. It was also once hypothesized that people who overpopulated the island and used its forest until it was gone, also caused the population to then collapse.
A new study reported in Nature has examined these questions through the spectrum of genetic data that was obtained from fifteen Rapanui individuals who lived on the island at a time between 1670 and 1950; remains from these people are now housed at the Musée de l'Homme, in Paris. The study authors did meet with the Comisión Asesora de Monumentos Nacionales in Rapa Nui (CAMN) to discuss the research and inquire about their concerns. An ongoing dialogue is also occurring to determine how to repatriate these remains.
The findings from the study have provided new evidence that refutes the idea that resource mismanagement cause the island's Polynesian population to collapse. The Pacific Islanders arrived on the island around 1250, and their presence did alter the island significantly, and the millions of palm trees that once grew on the island were lost.
"While it is well established that the environment of Rapa Nui was affected by anthropogenic activity, such as deforestation, we did not know if or how these changes led to a population collapse," noted senior study author Anna-Sapfo Malaspinas, an Associate Professor at the University of Lausanne, among other appointments.
But genetic data revealed in this study did not show signs of a population collapse, which would have been reflected in a sudden loss of genetic diversity in the samples that were analyzed.
"Our genetic analysis shows a stably growing population from the 13th century through to European contact in the 18th century. This stability is critical because it directly contradicts the idea of a dramatic pre-contact population collapse," explained first study author Bárbara Sousa da Mota, a graduate student at the University of Lausanne.
The high quality genetic data has also suggested that people from Rapa Nui and the Americas met before the appearance of Europeans on the scene. About ten percent of the Rapanui genome seems to come from Indigenous Americans. The distribution of that DNA in the genome suggests that there was contact between these groups in the 13th and 15th centuries, said first study author Víctor Moreno-Mayar, an Assistant Professor at the University of Copenhagen.
"While our study cannot tell us where this contact occurred, this might mean that the Rapanui ancestors reached the Americas before Christopher Columbus," added Malaspinas.
It's been thought that people who now live on Rapa Nui carry some ancestry from Indigenous Americans because of Europeans and their colonial actions, but this work has indicated that Rapanui Polynesians and Indigenous Americans contacted and mixed with one another before the appearance of Europeans in the Americas, said Sousa da Mota. "We believe this means that Rapanui were capable of even more formidable voyages across the Pacific than previously established."
Sources: University of Copenhagen, Nature