Craniofacial evolution in Polynesia: a geometric morphometric study of population diversity.

OBJECTIVES: This study tests differences in craniofacial size and shape attributed to demographic history and plastic responses to differing environments in the islands of Polynesia. The dispersal of modern humans into Polynesia provides a useful scenario to investigate the impact of migration on human craniofacial diversity.

METHODS: Three dimensional geometric morphometric techniques are used to examine morphological diversity within Oceanic population samples. The importance of geographic and climatic variables is quantified by partial linear regression.

RESULTS: The results show a homogeneous Polynesian morphology grouping in relation to neighboring regions. There is, however, considerable diversity within the Polynesian samples themselves. Natural selection due to environmental differences is not an important factor in the patterns of craniofacial diversity found in the samples.

CONCLUSIONS: Historical patterns such as migration and population isolation influence patterns of craniofacial morphology within Polynesia, and our results demonstrate that morphological diversity can evolve in populations isolated for a relatively short period of time.