Population Turnover in Remote Oceania Shortly after Initial Settlement.

Area of Science:

• Population Genetics
• Ancient DNA Analysis
• Oceanic Migration History

Background:

• The Lapita culture, associated with the First Remote Oceanians, spread across Remote Oceania starting around 2,900-2,600 years ago.
• Existing populations in Near and Remote Oceania show significant Papuan ancestry (>25%), suggesting later migrations beyond the initial Austronesian expansion.

Purpose of the Study:

• To investigate the genetic origins and migration patterns of ancient populations in Vanuatu and Tonga.
• To understand the sources and timing of Papuan ancestry introduction into Remote Oceania.

Main Methods:

• Genome-wide ancient DNA analysis of 14 individuals from Vanuatu (2900-150 BP).
• Analysis of genome-wide data from 185 present-day individuals across 18 islands.
• Fine-grained ancestry profiling to trace migration routes.

Main Results:

• The First Remote Oceanians were direct descendants of Austronesian speakers from Taiwan, with minimal Papuan admixture initially.
• Populations with high Papuan ancestry arrived in Vanuatu around 2300 BP, likely from the Bismarck Archipelago, not the Solomon Islands.
• Polynesian ancestry derives from distinct sources, indicating a third major migration stream into Remote Oceania.

Conclusions:

• The initial Austronesian expansion was followed by significant, distinct migration events introducing Papuan ancestry into Remote Oceania.
• Papuan ancestry in Vanuatu originated from the Bismarck Archipelago, while Polynesian ancestry involved different sources.
• These findings clarify the complex multi-stream migration history shaping the genetic landscape of Remote Oceania.