The genomic landscape of contemporary western Remote Oceanians

Arauna, L. R.; Bergstedt, J.; Choin, J.; Mendoza-Revilla, J.; Harmant, C.; Roux, M.; Mas-Sandoval, A.; Lemee, L.; Colleran, H.; Francois, A.; Valentin, F.; Cassar, O.; Gessain, A.; Quintana-Murci, L.; Patin, E.

doi:10.1101/2022.01.10.475623

bioRxiv · 10.1101/2022.01.10.475623

The genomic landscape of contemporary western Remote Oceanians

Arauna, L. R.·Bergstedt, J.·Choin, J.·Mendoza-Revilla, J.·Harmant, C.·Roux, M.·Mas-Sandoval, A.·Lemee, L.·Colleran, H.·Francois, A.·Valentin, F.·Cassar, O.·Gessain, A.·Quintana-Murci, L.·Patin, E.

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Abstract

The Vanuatu archipelago served as a gateway to Remote Oceania during one of the most extensive human migrations to uninhabited lands, ~3,000 years ago. Ancient DNA studies suggest an initial settlement by East Asian-related peoples that was quickly followed by the arrival of Papuan-related populations, leading to a major population turnover. Yet, there is uncertainty over the population processes and the sociocultural factors that have shaped the genomic diversity of ni-Vanuatu, who present nowadays among the worlds highest linguistic and cultural diversity. Here, we report new genome-wide data for 1,433 contemporary ni-Vanuatu from 29 different islands, including 287 couples. We find that ni-Vanuatu derive their East Asian- and Papuan-related ancestry from the same source populations and descend from relatively synchronous, sex-biased admixture events that occurred ~1,700-2,300 years ago, indicating a peopling history common to all the archipelago. However, East Asian-related ancestry proportions differ markedly across islands, suggesting that the Papuan-related population turnover was geographically uneven. Furthermore, we detect Polynesian ancestry arriving ~600-1,000 years ago to South Vanuatu in both Polynesian- and non-Polynesian-speaking populations. Lastly, we provide evidence for a tendency of spouses to carry similar genetic ancestry, when accounting for relatedness avoidance. The signal is not driven by strong genetic effects of specific loci or trait-associated variants, suggesting that it results instead from social assortative mating. Altogether, our findings provide insight into both the genetic history of ni-Vanuatu populations and how sociocultural processes have shaped the diversity of their genomes.

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Arauna, L. R., Bergstedt, J., Choin, J., Mendoza-Revilla, J., Harmant, C., Roux, M., Mas-Sandoval, A., Lemee, L., Colleran, H., Francois, A., Valentin, F., Cassar, O., Gessain, A., Quintana-Murci, L., Patin, E.. 2022-01-10. The genomic landscape of contemporary western Remote Oceanians. https://doi.org/10.1101/2022.01.10.475623

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