title: Brief communication: mitochondrial DNA variation suggests extensive gene flow from Polynesian ancestors to indigenous Melanesians in the northwestern Bismarck Archipelago.
abstract: Archaeological, linguistic, and genetic studies show that Austronesian (AN)-speaking Polynesian ancestors came from Asia/Taiwan to the Bismarck Archipelago in Near Oceania more than 3,600 years ago, and then expanded into Remote Oceania. However, it remains unclear whether they extensively mixed with indigenous Melanesians who had populated the Bismarck Archipelago before their arrival. To examine the extent of admixture between Polynesian ancestors and indigenous Melanesians, mitochondrial DNA (mtDNA) variations in the D-loop region and the cytochrome oxidase and lysine transfer RNA (COII/tRNA(Lys)) intergenic 9-bp deletion were analyzed in the following three Oceanian populations: 1) Balopa Islanders as AN-speaking Melanesians living in the northwestern end of the Bismarck Archipelago, 2) Tongans as AN-speaking Polynesians, and 3) Gidra as non-Austronesian-speaking Melanesians in the southwestern lowlands of Papua New Guinea. Phylogenetic analysis of mtDNA sequences revealed that more than 60% of mtDNA sequences in the Balopa Islanders were very similar to those in Tongans, suggesting an extensive gene flow from Polynesian ancestors to indigenous Melanesians. Furthermore, analysis of pairwise difference distributions for the D-loop sequences with the 9-bp deletion and the Polynesian motif (i.e., T16217C, A16247G, and C16261T) suggested that the expansion of Polynesian ancestors possessing these variations occurred approximately 7,000 years ago.
authors.affiliation: Department of Human Genetics, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan. juno-tky@umin.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Ohashi
authors.forename: Izumi
authors.initials: I
authors.lastname: Naka
authors.forename: Katsushi
authors.initials: K
authors.lastname: Tokunaga
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Inaoka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ataka
authors.forename: Minato
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Ohtsuka
mesh_terms: D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D044383:Black People / Q000235:genetics*; D016000:Cluster Analysis; D004272:DNA, Mitochondrial / Q000737:chemistry* / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D051456:Gene Flow; D005828:Genetics, Population; D006801:Humans; D008239:Lysine / Q000235:genetics; D008297:Male; D008542:Melanesia; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics; D011114:Polynesia; D012343:RNA, Transfer / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics*; D044465:White People / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D012343:RNA, Transfer; D003576:Electron Transport Complex IV; D008239:Lysine