ena-STUDY-UCSC-17-08-2017-18:20:41:597-33
Genetic ancestry of Rapa Nui (Easter Island, Chile) before and after European contact
Debates surrounding the origins and lifeways of the inhabitants of Rapa Nui (Easter Island), a remote island in the south-east Pacific, have endured for generations. Archaeological evidence substantiates the widely accepted view that the island was first settled by people of Polynesian origin, as late as 1200 Common Era (CE) [1–4]. What remains controversial, however, is the nature of events in the island's population history prior to the first historically attested contact with a European explorer in 1722 CE. Purported contact between Rapa Nui and South America is particularly contentious. A recent study reported signals of Native American admixture in present-day indigenous inhabitants of Rapa Nui [5–8]. Statistical modeling suggested that this genetic contribution might have occurred prior to the European contact [6]. Here we directly test the hypothesis that the Native American admixture of the current Rapa Nui population predates the arrival of Europeans with a paleogenomic analysis of seven individual samples excavated from Ahu Nau Nau, Anakena, dating to pre- and post-European contact, respectively. Despite challenging preservation, we were able to reconstruct complete mitochondrial genomes and low coverage autosomal genomes from five individuals. Comparative population genetic analyses showed that the analyzed individuals fall within the genetic diversity of present-day and ancient Polynesians. None of these individuals showed evidence of admixture with Native Americans, neither the pre- nor post-European contact samples. Our data thus suggest that the Native American admixture seen in contemporary Eastern Islanders does not go back to pre-European contacts with Rapa Nui.
Debates surrounding the origins and lifeways of the inhabitants of Rapa Nui (Easter Island), a remote island in the south-east Pacific, have endured for generations. Archaeological evidence substantiates the widely accepted view that the island was first settled by people of Polynesian origin, as late as 1200 Common Era (CE) [1–4]. What remains controversial, however, is the nature of events in the island's population history prior to the first historically attested contact with a European explorer in 1722 CE. Purported contact between Rapa Nui and South America is particularly contentious. A recent study reported signals of Native American admixture in present-day indigenous inhabitants of Rapa Nui [5–8]. Statistical modeling suggested that this genetic contribution might have occurred prior to the European contact [6]. Here we directly test the hypothesis that the Native American admixture of the current Rapa Nui population predates the arrival of Europeans with a paleogenomic analysis of seven individual samples excavated from Ahu Nau Nau, Anakena, dating to pre- and post-European contact, respectively. Despite challenging preservation, we were able to reconstruct complete mitochondrial genomes and low coverage autosomal genomes from five individuals. Comparative population genetic analyses showed that the analyzed individuals fall within the genetic diversity of present-day and ancient Polynesians. None of these individuals showed evidence of admixture with Native Americans, neither the pre- nor post-European contact samples. Our data thus suggest that the Native American admixture seen in contemporary Eastern Islanders does not go back to pre-European contacts with Rapa Nui.