The Development of Population Diversity at Chaco Canyon

Despite over a century of archaeological investigation at Chaco Canyon, the population diversity of this important regional center during the Pueblo II and early Pueblo III periods (ca A.D. 890–;1140) is poorly understood. The purpose of the present research was to investigate the level of population diversity at Chaco Canyon during this time period through quantitative genetic analysis of craniometric variation, as well as to present plausible models for the development of this diversity. Regional and extraregional population samples were included to provide meaningful biogeographical context, and to provide a basis for assessing the level of population diversity observed at Chaco Canyon. The results of this analysis indicate the best model for the development of population diversity at Chaco Canyon is based on aggregation of regional populations, possibly with some gene flow with Rio Grande groups. The level of diversity observed at Chaco Canyon is greater than that observed for various ancestral ethnolinguistic groupings comprised of multiple communities. These results indicate that Chacoan culture might have been composed of multiple ethnolinguistic groups with separate biogeographical affinities, all sharing a largely similar material culture. This study emphasizes the need for a more inclusive evaluation of cultural and sociopolitical complexity at Chaco, one that includes the investigation of material culture, architecture, and biological variation.