Genetic affinities between the Yami tribe people of Orchid Island and the Philippine Islanders of the Batanes archipelago

The family relationships inferred from the NRY Phylogeny suggested a low number of paternal founders and agreed with the genealogy of Wei and Liu (P < 0.01). Except for one Y short tandem repeat lineage (Y-STR), seen in two unrelated Yami families, no other Y-STR lineages were shared between villages, whereas mtDNA haplotypes were indiscriminately distributed throughout Orchid Island.The genetic affinity seen between Yami and Taiwanese aborigines or between Ivatan and the Philippine people was closer than that between Yami and Ivatan, suggesting that the Orchid islanders were colonized separately by their nearest neighbors and bred in isolation. However a northward gene flow to Orchid Island from the Philippines was suspected as Yami and Ivatan peoples both speak Western Malayo-Polynesian languages which are not spoken in Taiwan. Actually, only very little gene flow was observed between Yami and Ivatan or between Yami and the Philippines as indicated by the sharing of mtDNA haplogroup B4a1a4 and one O1a1* Y-STR lineage.The NRY and mtDNA genetic information among Yami tribe peoples fitted well the patrilocal society model proposed by Wei and Liu. In this proposal, there were likely few genetic exchanges among Yami and the Philippine people. Trading activities may have contributed to the diffusion of Malayo-Polynesian languages among them.Finally, artifacts dating 4,000 YBP, found on Orchid Island and indicating association with the Out of Taiwan hypothesis might be related to a pioneering stage of settlement, as most dating estimates inferred from DNA variation in our data set ranged between 100-3,000 YBP.Orchid Island, is located 49 nautical miles from the southeast coast of Taiwan along the Bashi (or Luzon) channel in the Pacific Ocean, and is home to the Yami tribe (also known as Tao). The Ivatan tribe people are inhabitants of Itbayat in the Batanes archipelago which is south of Orchid Island (Figure 1). The languages of Yami and Ivatan belongs to the Batanic sub