Where Pacific Islanders Come From Large DNA Study Distinguishes Main Genetic Groupings
By John Noble Wilford
The ancestral relationships of people living in the widely scattered islands of the Pacific Ocean, long a puzzle to anthropologists, may have been solved by a new genetic study, researchers reported.
In an analysis of the DNA of 1,000 individuals from 41 Pacific populations, an international team of scientists found strong evidence showing that Polynesians and Micronesians in the central and eastern islands have almost no genetic relationship to Melanesians, in the western islands like Papua New Guinea and the Bismarck and Solomons archipelagos.
The researchers also concluded that the genetic data show that the Polynesians and Micronesians are most closely related to Taiwan Aborigines and East Asians. They said this supported the view that these migrating seafarers originated in Taiwan and coastal China at least 3,500 years ago.
The findings were described Thursday in the online journal Public Library of Science Genetics (www.plosgenetics.org) by researchers led by Jonathan Friedlaender, professor emeritus of biological anthropology at Temple University. He was assisted in the data analysis by his wife, Francoise Friedlaender, an independent researcher. Other participants included scientists in the islands and at Marshfield Clinic Research Foundation, in Marshfield, Wisconsin.
“Our analysis,” the scientists wrote, “indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.”
Jonathan Friedlaender said in an interview that the evidence was substantial and solved “a number of issues about the migration and settlement of Pacific people.”
In particular, he and other anthropologists not involved in the study said, the genetic research supported the “fast-train” hypothesis. Increasing archaeological and linguistic evidence in recent years has suggested that ancestors of Micronesians and Polynesians moved through Indonesia and Melanesia without having any significant contact there, culturally or genetically.
An alternative argument, the “slow-boat” hypothesis, which had some support from male Y chromosome studies, raised the possibility that Polynesians were primarily Melanesians who had ventured on in their outrigger canoes. And a few anthropologists despaired of ever solving the mystery. Theirs was dubbed the “entangled bank” hypothesis.
The new genetic research, said Patrick Kirch, an anthropologist at the University of California, Berkeley, who is an authority on Pacific cultures, was “overwhelming biological evidence for a clear population movement out of Southeast Asia and Taiwan to Polynesia.”
Kirch, who did not participate in the genetic study, said that it reinforced research showing that Polynesian speech patterns were unrelated to Melanesian languages as well as buttressed discoveries of the distinctive Lapita pottery across the Pacific. All of the findings suggest links to Taiwan and China, not Melanesia. “The combination of evidence shows we really can read this history,” he said.
As Friedlaender said, “If it wasn’t exactly an express train, it was pretty fast, and very few passengers climbed aboard or got off along the way.”
In the research, scientists examined more than 800 genetic markers known to be useful in distinguishing the ancestry of people. These involved mitochondrial DNA, passed down through females, and the Y chromosomes in males. Previous investigations along these lines had been conducted on a much smaller scale, Friedlaender said.
Originally published by The New York Times Media Group.
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