The Formation of Proto-Austronesians: Insights from a Revised Phylogeography of the Paternal Founder Lineage.

Objectives Previous studies suggested that the Y-chromosome haplogroups O2-N6-B451-AM01756 and O1a-M119 are two founder lineages of proto-Austronesians at about five thousand years ago. The objective of this study was to investigate the formation of proto-Austronesians from the perspective of the paternal gene pool. Materials and methods In this study, we developed a highly evised phylogenetic tree with age estimates for haplogroup O2-N6 and early branches of O1a-M119 (M110, F1036, and F819). In addition, we also explored the geographical distribution of eight sub-branches of O2-N6 and O1a-M119, and spatial autocorrelation analysis was conducted for each sub-branch. Results The paternal lineage combination of proto-Austronesians is a small subset of a diverse gene pool of populations from the mainland of East Asia. The distribution map and results of the spatial autocorrelation analysis suggested that the eastern coastal region of northern China is likely the source of lineage O2-N6 while the coastal region of southeastern China is likely the diffusion center of early branches of O1a-M119. We developed an evolutionary diagram for Austronesians and their ancestors in the past 18,000 years. Discussion We proposed that the millet farming community in North China is the common ancestor group of the Austronesians and the Han people, while the diverse ancient people in the southeast coastal areas of East Asia form the common ancestor group of the Austronesians and the East Asian mainland population. The demographic history of multiple ancestral groups of the most recent common ancestor group itself in the more ancient period is helpful to understand the deep roots of the genetic components and cultural traditions of Austronesians.