Evrim Yazgin
Cosmos science journalist
Archaeologists have studied the genomes of 42 individuals spanning 2,500 years from Papua New Guinea and surrounding islands.
Despite their critical role in the human history of the Pacific region, this group’s genetic diversity is understudied, the researchers say. Their findings are in a paper published in the journal Nature Ecology & Evolution.
Humans reached the western Pacific Islands at least 50,000 years ago. Ancient humans made their way from places like the Aru Islands, New Guinea, the Bismarck Archipelago and the Solomon Islands to the remote Pacific Islands – the last islands on Earth to be settled by people.
The new research used accelerator mass spectrometry (AMS) to date samples from the 42 individuals.
Genetic data revealed different dispersal events which affected the DNA of ancient Papua New Guinea communities.
The oldest individuals, dating to about 2,500 years ago, had more Papuan-related DNA. By about 2,100 years ago, the local communities were reproducing with more people coming from East and Southeast Asia.
“These results and the inferred admixture dates suggest a centuries-long delay in genetic mixture with local communities after the arrival of populations with Asian ancestry,” the authors write.
“Two geographically close communities on the South Coast, AMS dated to within the past 540 years, diverge in their genetic profiles, suggesting differences in their interaction spheres involving groups with distinct ancestries,” they add. “The inferred split time of these communities around 650 years before present coincides with intensified settlement activity and the emergence of regional trade networks.”
The authors relate these genetic findings to oral traditions of local people who recall relocation events in their communities’ past.
“The reason for the separation of the two communities, despite no evident geographical barriers, remains enigmatic and might point to the introduction of a cultural barrier connected to different interactions of the two groups after relocation,” the authors say.
