Demographic History of Oceania Inferred from Genome-wide Data

Background The human history of Oceania comprises two extremes the initial colonizations of Near Oceania, one of the oldest out-of-Africa migrations, and of Remote Oceania the most recent expansion into unoccupied territories Genetic studies, mostly using uniparentally inherited DNA have shed some light on human origins in Oceania, particularly indicating that Polynesians are of mixed East Asian and Near Oceanian ancestry Here, we use similar to 1 million single nucleotide polymorphisms (SNPs) to investigate the demographic history of Oceania in a more detailed manner Results We developed a new approach to account for SNP ascertainment bias used approximate Bayesian computation simulations to choose the best-fitting model of population history, and estimated demographic parameters We find that the ancestors of Near Oceanians diverged from ancestral Eurasians similar to 27 thousand years ago (kya), suggesting separate initial occupations of both territories The genetic admixture in Polynesian history between East Asians (similar to 87%) and Near Oceanians (similar to 13%) occurred similar to 3 kya, prior to the colonization of Polynesia. Fijians are of Polynesian (similar to 65%) and additional Near Oceanian (similar to 35%) ancestry not found in Polynesians with this admixture occurring considerably after the initial settlement of Remote Oceania Our data support a greater contribution of East Asian women than men in the admixture history of Remote Oceania and highlight population substructure in Polynesia and New Guinea Conclusions Despite the inherent ascertainment bias genome-wide SNP data provide new insights into the genetic history of Oceana Our approach to correct for ascertainment bias and obtain reliable inferences concerning demographic history should prove useful in other such studie