Overview:
A groundbreaking DNA study of ancient remains in Palau shows that the islands’ first settlers had a unique ancestry unlike other Pacific islands. Researchers say the genetic mix seen today in Palauans has remained largely unchanged for nearly 3,000 years — one of the longest records of population continuity in Remote Oceania.
Research shows 2,800 years of genetic continuity unlike other Pacific islands, challenging earlier ideas about migration across Remote Oceania
By: L.N Reklai
KOROR, Palau — A new DNA study of ancient human remains in Palau shows that the islands’ earliest settlers had a different ancestry pattern than people who settled many other Pacific islands, and that their descendants have lived in the archipelago with little change for nearly 3,000 years.
The research, published this month in the journal Cell, found that the earliest known inhabitants of Palau had a genetic mix of about 60% East Asian ancestry and 40% Papuan ancestry. Scientists say that same genetic pattern can still be seen in modern-day Palauans.
The findings suggest one of the longest stretches of population continuity ever recorded in Remote Oceania.
The study was led by researchers including Yue-Chen Liu, Joanne Eakin, Jolie Liston, Rosalind Hunter-Anderson, Ron Pinhasi and David Reich.
Archaeological evidence shows people first arrived in the Palau archipelago about 3,200 years ago. Until now, scientists had not analyzed genome-wide DNA from ancient human remains in the islands.
Researchers examined 37 skeletal specimens from four archaeological sites, including the Ngkeklau area in northeastern Babeldaob and burial caves at Ngermereues Ridge and the Rock Islands of Ucheliungs and Omedokl.
From those remains, scientists were able to recover full genome data from 21 individuals.
Seventeen radiocarbon dates were produced from 13 individuals. Eleven samples were directly dated, including two from near the time when people first settled Palau. Those remains were dated between about 2,924 and 2,710 years ago and between 2,776 and 2,495 years ago.
Researchers also studied carbon and nitrogen isotopes to better understand the individuals’ lives and environment.
The team compared the Palau data with previously reported genetic information from nearby regions. They found that the East Asian ancestry in the ancient Palauan individuals is more closely related to people from eastern Indonesia, including Aru Namara and Tanjung Pinang on Morotai Island in Northern Maluku, than to early populations in the southwest Pacific or the Mariana Islands.
The study also showed that all ancient individuals tested from Palau had significant Papuan ancestry. In this research, “Papuan” refers to populations whose primary roots come from New Guinea, the Bismarck Archipelago and the Solomon Islands.
Scientists found that the Papuan ancestry in early Palauans is most closely related to people from the highlands of New Guinea.
The results suggest that the mixing of East Asian and Papuan populations happened centuries before people migrated to Palau.
Researchers said this was unexpected because earlier models predicted that Papuan ancestry would have mixed with Pacific populations around the same time it appeared in other parts of Remote Oceania, roughly 2,500 to 2,000 years ago.
“A natural expectation was that the admixture of Papuan ancestry in Palauan ancestors occurred around the same time as in other remote Oceanians,” the researchers wrote, noting that the earlier mixing found in the study was surprising.
The findings also challenge earlier migration models based on historical linguistics.
Instead, the study suggests that the ancestors of the first Palauans were already a mixed population nearly a thousand years before major human movements spread across Remote Oceania.