Microevolution and migration in the Pacific.

Abstract

Archaeological, linguistic, and ethnocultural studies suggest the Pacific was colonized by two, or possibly three, genetically distinct groups of people. Australoids moved first into New Guinea and Australia, followed by Papuan-speaking people, who penetrated as far as Santa Cruz in the Solomons. Austronesian speakers began their migrations 6,000 years ago and mixed with preexisting populations to a varying extent until they finally reached the unpopulated islands. Here, in Samoa and Tonga, they developed the cradle of Polynesian culture, which spread to the central Pacific and from there north to Hawaii and west to New Zealand. Detailed genetic studies have indicated that, in New Guinea, geographical propinquity is an important determinant of genetic similarity between populations. A wider survey indicates, however, that Austronesian speakers have more in common, despite great geographical separation than is true for Papuan speakers. In the Banks and Torres Islands and the Solomons, Polynesian "Outliers" can be differentiated from other Melanesian island populations, while for the Pacific as a whole it is shown that Amerindian populations cluster with north Mongoloids and Polynesian populations cluster with south Mongoloids, with Australian Aborigines and New Guinea Papuans maintaining separate identities. It is concluded that Polynesians originated from a south Mongoloid population, losing a number of specific marker genes along their migratory path, and becoming modified genetically before establishing themselves in the Polynesian centre of dispersal.