Cultural Interaction and Biological Distance Among Postclassic Mexican Populations Corey Steven Ragsdale
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University of New Mexico UNM Digital Repository Anthropology ETDs Electronic Theses and Dissertations 5-1-2015 Cultural interaction and biological distance among Postclassic Mexican populations Corey Steven Ragsdale Follow this and additional works at: https://digitalrepository.unm.edu/anth_etds Part of the Anthropology Commons Recommended Citation Ragsdale, Corey Steven. "Cultural interaction and biological distance among Postclassic Mexican populations." (2015). https://digitalrepository.unm.edu/anth_etds/55 This Dissertation is brought to you for free and open access by the Electronic Theses and Dissertations at UNM Digital Repository. It has been accepted for inclusion in Anthropology ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected]. i Corey Steven Ragsdale Candidate Anthropology Department This dissertation is approved, and it is acceptable in quality and form for publication: Approved by the Dissertation Committee: Heather JH Edgar, Chairperson Osbjorn Pearson Hillard Kaplan Andrea Cucina Frances Berdan ii CULTURAL INTERACTION AND BIOLOGICAL DISTANCE AMONG POSTCLASSIC MEXICAN POPULATIONS by COREY STEVEN RAGSDALE B.A., Anthropology, California State University, San Bernardino 2009 M.S., Biological Anthropology, University of New Mexico, 2012 DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Anthropology The University of New Mexico Albuquerque, New Mexico May, 2015 iii CULTURAL INTERACTION AND BIOLOGICAL DISTANCE AMONG POSTCLASSIC MEXICAN POPULATIONS by Corey Steven Ragsdale B.A., Anthropology, California State University, San Bernardino 2009 M.S., Anthropology, University of New Mexico, 2012 Ph.D., Anthropology, University of New Mexico, 2015 ABSTRACT Human population structure is influenced by cultural and biological interactions. Little is known regarding to what extent cultural interactions effect biological processes such as migration and genetic exchange among prehistoric populations. In this study, I draw upon archaeological and ethnohistoric research to investigate the interaction of biology and culture among Postclassic period (AD 900-1519) Mexican populations. The central question for this project is: how did processes of economic exchange and political expansion affect genetic exchange among Postclassic period Mexican populations? To address this question, various biological distance analyses derived from dental morphological traits were employed to investigate inter- and intra-regional population interaction. These biological distances were further compared with distances inter- regionally, based on models of cultural interaction to evaluate the effects of geographic distances, political and economic interactions, shared migration history, and shared iv cultural/linguistic group. Cultural effects on biological population structure were further evaluated at the regional and site level using both conventional and innovative statistical approaches. My results show that shared migration and trade are correlated with biological distances, but geographic distance is not. Trade and political interaction are also correlated with biological distance when combined in a single variable. These results indicate that trade and political relationships affected population structure among Postclassic Mexican populations. When viewed regionally, there is high similarity among groups in the Central Mexico and the Huasteca/Maya regions, and low similarity among groups in West and Northern Mexico. These results suggest high levels of gene flow among groups in these regions. Results of the analyses of individual sites indicate that important economic, political, or religious centers in Central Mexico and the Huasteca/Maya regions have high variation among individuals, but not in West and Northern Mexico. I conclude that differences in population structure exist among the regions throughout Mexico, and that population structures are affected by differences in economic, political, and/or religious structure. I further conclude that trade likely played a major role in shaping patterns of interaction between populations. This study also shows that the biological distance data support the migration histories described in ethnohistoric sources. v Table of Contents Chapter 1: Introduction Introduction 1 Theoretical approaches 3 Archaeological and ethnohistoric accounts of population interaction 7 Population interaction in biological anthropology 13 Statistical analyses 18 Dissertation outline 20 Chapter 2: Modeling cultural effects on phenetic distances among Postclassic Mexican and American Southwest populations. Introduction 22 The archaeological and ethnohistoric records 23 Previous biological distance studies 28 Materials 30 Methods 33 Results 41 Discussion 45 Conclusion 48 Chapter 3: Cultural and biological distance in Postclassic period Mexico Introduction 50 Previous biological distance studies 53 vi Materials and Methods 55 Results 68 Discussion 73 Conclusion 80 Chapter 4: Regional population structure in Postclassic Mexico Introduction 83 Regional interaction in Postclassic Mexico 84 Previous research in Pre-contact Mexico population structure 90 Materials 91 Methods 94 Results 99 Discussion 109 Conclusion 112 Chapter 5: Conclusions 115 Bibliography 131 Appendices 148 1 CHAPTER 1: INTRODUCTION Human population structure is influenced by cultural and biological interactions. How do cultural interactions affect biological processes such as migration? This question is central to biocultural and bioarchaeological studies globally. In this study, I draw upon archaeological and ethnohistoric research to investigate the interaction of biology and culture among Postclassic period (AD 900-1519) Mexican populations. The central question for this project is: how did processes of economic exchange and political expansion affect genetic exchange among Postclassic period Mexican populations? To address this question, phenetic distances derived from dental morphological traits were compared with distances derived from political and economic relationships, geographic distances, shared migration history, and shared cultural/linguistic group. Phenetic similarity among groups approximates genetic similarity (Scott and Turner, 1997; Hanihara, 2008; Ricaut et al. 2010), so phenetic distances are appropriate for determining dissimilarity among populations using morphological features. This dissertation is concerned with population variation, as interpreted through biological distance studies. Patterns of population variation in pre-contact Mexico were affected by migration associated with widespread trade networks, endemic warfare, imperial expansion, and rapid population growth. The archaeological and ethnohistoric records provide a wealth of information about migration history and population interaction from as early as the first known civilization in Mesoamerica, the Olmec (1500-500 BC). For this project, migration refers to the movement of multiple individuals 2 to a different environment. These movements may occur as a small group of individuals acting based on common motives, or as large social groups whose actions are coordinated by a central authority (Cabana and Clark, 2011). Migrations throughout Mexico differed in scale: from the large and long-distance migrations of the nomadic Chichimec populations in the North, to settlements of several families within the Aztec Empire to the frontiers of the Gulf Coast, to the intentional resettlement of merchants to areas of high trade areas. By the Postclassic period (AD 900-1519), economic and political relationships connected virtually every population throughout Mexico. What is not known through the archaeological and ethnohistoric records is how these relationships shaped patterns of migration and genetic exchange among populations across the various regions of Mexico. The results of this project can be used to build models for understanding relationships between culture and biology in regions around the world where the archaeological and ethnohistoric records are not as strong as in Mexico. This study blends biological distance data with models derived from cultural ecology, the study of human adaptations to their cultural and physical environments, including the distribution of wealth and power among cultural groups (Steward, 1990). A holistic approach to understanding population interaction and migration, such as that proposed here, is optimal for gaining a better understanding of the effects of imperial expansion, control of resources, intensified trade, and shared ideology on patterns of migration among prehistoric human populations. 3 Theoretical approaches I am particularly interested in how political-economic processes affect population interaction and population structure. Political economy is a broad approach to investigating the relationships between people, economies and political structures (Gilpin and Gilpin 1987). From the perspective of biological anthropology, political economy theory can be used to understand how separate communities are connected through larger historical (or archaeological) political-economic processes that affect human biology (Goodman and Letherman, 1998). One aspect of political economy relevant to this project is the relationship between biological variation and the social/cultural relationships associated with resource availability and labor. Populations around Mexico during the Postclassic period were politically organized into city-state