Papuan Admixture Predated the Settlement of Palau

TL;DR

Ancient DNA from Palau shows that the mixing of Papuan and East Asian ancestry happened before the island was first settled, unlike in other parts of Remote Oceania.

Contribution

The study provides genome-wide ancient DNA data from Palau, revealing pre-settlement admixture between Papuans and East Asians.

Findings

All ancient Palauans had about 60% East Asian and 40% Papuan ancestry, similar to modern Palauans.

Papuan ancestry segments in the oldest individuals indicate admixture occurred before settlement.

This contrasts with the southwest Pacific, where Papuan admixture came later.

Abstract

The first people reached Remote Oceania before 3000 years ago (BP), arriving roughly simultaneously in the southwest Pacific, the Marianas Archipelago, and Palau. However, no genome-wide ancient DNA data have been available from Palau, a gap we address by reporting 21 individuals from four archaeological sites dating between 2900 and 500 BP. All had approximately 60% ancestry related to East Asians and 40% to Papuans, similar to present-day Palauans, the longest stretch of population continuity anywhere in Remote Oceania. The lengths of contiguous Papuan ancestry segments in the oldest individuals show that major admixture between Papuans and East Asians in the ancestors of all sampled Palauans began prior to first settlement. This differs from the pattern in the southwest Pacific, where sampled individuals of the Lapita archaeological culture from three different islands had almost entirely East Asian ancestry, with large amounts of Papuan admixture observed only hundreds of years later.

Ancient DNA data from Palau reveals long-standing genetic continuity, and shows that the major admixture between Papuans and East Asians that occurs in many Remote Oceanians today, in some cases was present in first settlers more than 3200 years ago.

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