THE ORIGINS OF THE POLYNESIANS - AN INTERPRETATION FROM MITOCHONDRIALLINEAGE ANALYSIS

Using mitochondrial lineage analysis of 1,178 individuals from Polynes ia, the western Pacific, and Taiwan, we show that the major prehistori c settlement of Polynesia was from the west and involved two or possib ly three genetically distinct populations. The predominant lineage gro up, accounting for 94% of Polynesian mtDNA, shares a 9-bp COIL/tRNA(Ly s) intergenic deletion and characteristic control region transition va riants, compared to the Cambridge reference sequence. In Polynesia, th e diversity of this group is extremely restricted, while related linea ges in Indonesia, the Philippines, and Taiwan are increasingly diverse . This suggests a relatively recent major eastward expansion into Poly nesia, perhaps originating from Taiwan, in agreement with archaeologic al and linguistic evidence, but which experienced one or more severe p opulation bottlenecks. The second mitochondrial lineage group, account ing for 3.5% of Polynesian mtDNA haplotypes, does not have the 9-bp de letion and is characterized by an A-C transversional variant at nt pos ition 16265. Specific oligonucleotides for this variant were used to s elect individuals from the population sample who, with other sequences , show that the Polynesian lineages were part of a diverse group in Va nuatu and Papua New Guinea. The very low overall diversity of both lin eage groups in Polynesia suggests there was severe population restrict ion during the colonization of remote Oceania. A third group, represen ted by only four individuals (0.6%) in Polynesia but also present in t he Philippines, shares variants at nt positions 16172 and 16304. Two P olynesians had unrelated haplotypes matching published sequences from native South Americans, which may be the first genetic evidence of pre historic human contact between Polynesia and South America.