Genetic studies provide strong evidence that all Polynesians descend from a single ancestral group that expanded from Island Southeast Asia (ISEA) into Remote Oceania some 3,500 to 2,500 years ago, giving rise to the Polynesians.
The new study, published in Nature Ecology and Evolution, found that the settlement of remote Oceania involved multiple migrations and that the first settlers may have paused for several generations on certain islands on their way to more distant islands, such as Hawaii and Easter Island.
To reach more distant islands, such as Hawaii, the Marquesas, and Easter Island, the first Polynesian settlers would have had to navigate thousands of miles across vast stretches of open ocean, navigating by the stars and currents to find small islands that were often far apart.
"The remarkable dispersal of humans into Remote Oceania is a great testament to the skill, resilience, and courage of our ancestors. These findings offer unprecedented insights into the seafaring abilities and navigational skills of humans thousands of years ago," says lead author Frido Welker, an assistant professor of anthropology at Uppsala University in Sweden.
The researchers created the detailed genetic map of these ancient people using DNA from human bones found on archaeological sites around the Pacific. They collected genetic data from 53 individuals who lived in the Pacific Islands between 1,000 and 250 years ago, representing nine different island groups (including Hawaii, the Cook Islands, and Easter Island) and spanning 2,000 years of history.
According to the study's co-author, Anders Gotherstrom of the University of Stockholm, the ancient DNA contains valuable information. "The DNA in the teeth of these ancient individuals is extremely well preserved, providing a goldmine of information about the genetic structure of past populations and their demographic history."
Key findings:
• There were multiple migrations. The first was into Fiji and Vanuatu about 3,500 years ago. The second migration spread Lapita-style pottery to Samoa, Tonga, and the Marquesas Islands around 2,800 years ago. Subsequent migrations eventually settled the central and eastern islands, such as Hawaii and Easter Island.
• Pauses along the way. The first settlers may have stopped on certain islands for several generations before moving on. For instance, the Cook Islands were settled by people who paused in Tonga or Samoa.
• Admixture with other groups. The genes of some of the ancient settlers who reached more distant places suggest they may have mixed with other groups that were living on those islands already, such as the Papuans of New Guinea.
• Population fluctuations. Some island groups experienced marked population declines, for instance in Fiji about 1,000 years ago, possibly due to conflict, epidemics, or environmental changes.
The study, which involved dozens of scientists from various countries, provides a comprehensive view of the genetic history of the first humans to settle the remote islands of the Pacific Ocean. The genetic information obtained also has important implications for understanding the biological adaptations that allowed humans to thrive in these environments, paving the way for future studies on the evolution and resilience of the Polynesian people.
