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Ref ID: 36573
Ref Type: Thesis-PhD
Authors: Stefan, Vincent Hart
Title: Craniometric variation and biological affinity of the prehistoric Rapanui (Easter Islanders): their origin, evolution, and place in Polynesian prehistory
Date: 2000
Place of Publication: Albuquerque
Publisher: University of New Mexico
Type: PhD
Abstract: The origin, migration and evolution of Polynesian populations, in particular the Rapanui (Easter Islanders), have been the center of controversy for many years. Archaeological, linguistic and genetic/serological data have played instrumental roles towards resolving these disputes thus far. Several models have been developed which have addressed the origins of the prehistoric population that colonized Rapa Nui (Easter Island). Hypotheses have been designed from these models, and tested using cranial metric traits from prehistoric Rapanui, east Polynesian and coastal Peruvian skeletal samples: (1) the prehistoric Rapanui population have the closest biological affinity with the Marquesas Islands population
(2) the Rapanui population exhibit no evidence of in situ cranial evolution, reflecting the relative homogeneity of the “Polynesian peoples”
(3) the Rapanui population does not exhibit close biological affinity with South American populations, reflecting a lack of significant gene flow between Rapa Nui and South America. Craniometric data were collected from Rapanui (349), east Polynesian Mo'orea - 24, Tahiti - 66, Huahine - 1
Tuamotu Archipelago - 44), and coastal Peruvian (47) crania curated in Rapa Nui, the United States, South America and Europe. All data were corrected for sex and shape variation, tested for intra- and inter-observer error, and analyzed utilizing a wide range of statistical methods. The results were compared to the expected patterns of variation and relatedness produced by the microevolutionary forces of genetic drift due to isolation by geographic distance and gene flow via migration. The cranial phenotypic homogeneity of the east Polynesian populations was not supported by the results of the univariate and multivariate analyses of the metric traits. Significant among-group variation existed in the east Polynesian populations. The examination of the Mahalanobis's generalized distances, observed <italic>R</italic>-matrices, and estimated within-group kinship values indicate that the prehistoric Rapanui had the strongest affinities with the Gambier Islands population, followed closely by the Tuamotu Archipelago population. The Rapanui and east Polynesian data exhibited patterns of biological variation indicative of the microevolutionary processes of genetic drift and gene flow. Though the colonizing population of Rapa Nui remained relatively isolated, slight levels of migration with neighboring islands was indicated. This study incorporated both model-free and model-bound population genetics approaches to investigate the origins and subsequent evolution of the prehistoric Rapanui. In addition, this research illustrated the utility of quantitative traits in population genetic studies. The results obtained should encourage the implementation of model-bound methods of analysis for all investigations of biological affinity when using skeletal samples to represent prehistoric populations. The techniques used in this investigation of the origins and evolution of the prehistoric Rapanui will have broad reaching applications in future Polynesian bioanthropological research.
Date Created: 9/21/2002
Department: Department of Anthropology