Delineating the dispersal of sub-haplogroup O2a2b-P164 among Austronesian populations
This article reports on an exploration of the Y-chromosome sub-haplogroup O2a2b-P164 in Austronesian populations. We found that the P 164  mutation is observed at low frequencies (low single digits) in east mainland Asia and experiences fluctuations in insular populations of Near and Far Oceania likely the result of random drift as migrants settled islands to the south and east. Moderate to high abundance of the P 164 mutation is seen in the West Pacific including the Ami aborigines of Formosa (36%) and the Filipinos of Mindanao (50%) as well as in the Kiritimati of Micronesia (70%), and Tonga and Samoa of West Polynesia (54% and 33%, respectively), and it drops to low frequencies (low single digits) and low 10s in populations of East Polynesia. The network analyses based on Y-STR haplotype diversity indicate a biphasic P 164 distribution; in Near Oceania, the network analyses exhibit randomly dispersed singletons from different populations and limited population structure while in the communities of Polynesia and Micronesia considerable inter- and intra-population haplotype sharing and nodes separated by single mutations suggest extensive haplotype and population affinity. The MDS plot illustrates limited partitioning of Austronesian populations except for communities at the geographical fringes of their domain. The observed affinities, as well as the ages and diversity values within the P 164 sub-haplogroup among Austronesian populations signals an ancestral migration route and relationships that link the Ami of Taiwan with distant communities in West and East Polynesia, Micronesia, and the Maori of New Zealand. In addition, high resolution sequencing of the Austronesian Y chromosome indicate that the P 164 lineage originated about 19,000 ya and then split into three branches separating the Ami aborigines, Southeast Asian and Polynesian/Micronesian populations about 4,700 ya, roughly coinciding with the initiation of the Austronesian diaspora. Y-chromosomes re-sequencing demonstrated that all Polynesian and Micronesian examined belong to a specific sub-haplogroup, FT 257096 , which separated from the rest of the P 164 chromosomes about 2,900 ya, early during the Austronesian expansion.