Ancient DNA suggests people from Philippines may have settled Mariana Islands

Dec. 22 (UPI) -- New research suggests people from the Philippines may have first settled the Mariana Islands. According to the study, published online this week in the journal PNAS, early inhabitants of the Mariana Islands and Polynesia shared common ancestors.

Numerous studies have investigated the origins of the first Polynesian settlers, but little attention has been given to the peopling of the Mariana Islands, situated more than 1,600 miles east of the Philippines.

Positioned next the world's deepest ocean trench in the Western Pacific, the Mariana Islands were settled roughly 3,500 year, only slightly earlier than the initial peopling of Polynesia, roughly 5,000 miles east-southeast.

"We know more about the settlement of Polynesia than we do about the settlement of the Mariana Islands," first author Irina Pugach, researcher at the Max Planck Institute for Evolutionary Anthropology in Germany, said in a news release.

To better understand the origins of the people who first arrived on the Marianas, researchers analyzed ancient DNA recovered from a pair of skeletons found in Guam's Ritidian Beach Cave.

Guam, which is the largest and southernmost of the Mariana Islands, was settled roughly 1,400 years after the first human settlements were established in the Marianas.

The analysis revealed a strong link between the ancient skeletons and populations from the Philippines.

"These findings strengthen the picture that has emerged from linguistic and archaeological studies, pointing to an Island Southeast Asia origin for the first settlers of the Marianas," said co-author Mike T. Carson, an archaeologist at the Micronesian Area Research Center at the University of Guam.

Researchers also identified genetic similarities between the Guam skeletons and early Lapita individuals from Vanuatu and Tonga, a pair of islands in the South Pacific, situated a few thousands miles south-southeast of the Marianas.

"This suggests that the Marianas and Polynesia may have been colonized from the same source population, and raises the possibility that the Marianas played a role in the eventual settlement of Polynesia," Pugach said.

Because the research was based on only two skeletons -- the remains of people who arrived 1,400 years after the Marianas first were peopled -- the origins of the earliest Marianas settlers can't yet be confirmed beyond a doubt.

"The peopling of Guam and the settlement of such remote archipelagos in Oceania needs further investigation," said Mark Stoneking, Max Planck researcher and senior author of the new paper.