Human Population History in Vanuatu

[Angela]

See:
https://www.sciencedirect.com/science/article/abs/pii/S096098222031366X

"[h=2]Highlights[/h]•New ancient DNA supports a shift in ancestry during early migrations to Vanuatu
•A single spread from New Britain can explain most of the ancestry of later groups
•More recent Polynesian migrations contributed both cultural and genetic legacies


[h=2]Summary[/h]The archipelago of Vanuatu has been at the crossroads of human population movements in the Pacific for the past three millennia. To help address several open questions regarding the history of these movements, we generated genome-wide data for 11 ancient individuals from the island of Efate dating from its earliest settlement to the recent past, including five associated with the Chief Roi Mata’s Domain World Heritage Area, and analyzed them in conjunction with 34 published ancient individuals from Vanuatu and elsewhere in Oceania, as well as present-day populations. Our results outline three distinct periods of population transformations. First, the four earliest individuals, from the Lapita-period site of Teouma, are concordant with eight previously described Lapita-associated individuals from Vanuatu and Tonga in having almost all of their ancestry from a “First Remote Oceanian” source related to East and Southeast Asians. Second, both the Papuan ancestry predominating in Vanuatu for the past 2,500 years and the smaller component of Papuan ancestry found in Polynesians can be modeled as deriving from a single source most likely originating in New Britain, suggesting that the movement of people carrying this ancestry to Remote Oceania closely followed that of the First Remote Oceanians in time and space. Third, the Chief Roi Mata’s Domain individuals descend from a mixture of Vanuatu- and Polynesian-derived ancestry and are related to Polynesian-influenced communities today in central, but not southern, Vanuatu, demonstrating Polynesian genetic input in multiple groups with independent histories."

 

[Tamakore]

This study adds to the aDNA studies that have settled the debate between the "express train" and "slow boat" models of the settlement of Remote Oceania. It is now clear that the first settlers, the Lapita people, were largely of Taiwanese origin, speaking a Taiwanese (i.e. Austronesian) language. In less than one thousand years they expanded from Taiwan to Western Polynesia, with almost no admixture with other populations they had contact with along the way.

About 500 years after the Lapita expansion, Papuan-Melanesian people from New Britain (who had probably adopted both Lapita sailing techniques and Austronesian languages) expanded to the Pacific island groups previously colonized by the Lapita people. In Vanuatu, New Caledonia and (to some extent) Fiji they became dominant, replacing the Lapita culture. There were also male-biased migrations to Western Polynesia (Tonga and Samoa). As a result, about 20% of modern Polynesian autosomal DNA is of Papuan (New Britain) origin.

Papuan ancestry is most noticeable in the Y-DNA haplogroups of Polynesians. In some Polynesian populations, such as Maori, Y haplogroup C-M208 (which reached New Britain about 40,000 years ago) is the majority haplogroup, whilst haplogroups of Taiwanese origin (such as O-P201) are in the minority.

In contrast, the mtDNA haplogroups of Polynesian people are almost entirely of Taiwanese origin (mainly haplogroup B4a2a1). This is evidence that the Papuan-Melanesian migrants to Western Polynesia about two thousand years ago were mainly males.

So, this new study is further confirmation that the "express train" model put forward by Jared Diamond and Peter Bellwood is the correct one.