Doctoral Dissertation Improvement: Mesoamerican Population Structure and Interregional Interaction

在国家科学基金会的支持下，布莱恩·奥布里将对公元600-1000年间整个中美洲地区的26个骨骼种群进行生物考古研究。从考古和民族史学数据中可以推断出这一时期巨大的社会政治和人口变化，但目前对于中美洲次区域之间相互作用的性质还没有达成共识。这项研究并不特别关注这些变化的原因，而是关于是否可以通过对牙齿变异的分析来从生物学上检测到可能发生的任何人口结构变化。从历史上看，研究人员假设，在古典和后古典时期，墨西哥中部的人口在不同的时间向南迁徙到玛雅地区。尽管对墨西哥中部在整个中美洲地区的影响程度存在重大争论，但大多数人认为确实发生了移民，考古接触证据表明人口迁移。尽管玛雅-墨西哥关系对中美洲史前的重要性被认为是显而易见的，但这将是第一次足够规模的生物考古研究来帮助解决这一问题。在一项研究中纳入来自中美洲各地的材料，对于回答研究中提出的研究问题至关重要。这项研究的范围将允许检测种群结构随时间的变化，并隔离从外部流入玛雅地区的基因来源。尤其重要的是，隔离每个子区域内优先与其各自区域外的站点相互作用的特定站点。这项研究的具体任务是1)评估三个亚区中每个亚区内的位点的生物学距离，以检测异常值；2)计算每个亚区的遗传杂合度水平，并将各个位点与这些期望值进行比较；3)比较每个亚区内表现出高于预期的遗传杂合度水平的特定位点的生物学距离。确定来自不同次区域的特定地点之间偏离预期的相互作用范围，将有助于阐明墨西哥中部对玛雅地区的影响的性质。该项目的独特之处在于，它是使用公制和非公制牙齿数据对中美洲生物亲和力进行的最大规模研究，并且是第一个记录所有个体的牙釉质结合部(CEJ)和牙冠测量的项目。这项研究的学术价值来自于它促进了我们目前对中美洲泛区域相互作用的理解，以及对目前关于CROW和CEJ测量之间的一致性的文献的补充。该项目的更广泛的影响是它对中美洲历史上一个重要时期的研究做出了贡献。此外，研究人员将能够获取来自大约3500人的原始数据，而不是摘要数据，以便与他们自己的数据进行比较，或者用于这些数据的其他统计应用。

With National Science Foundation support, Bryan Aubry will conduct bioarchaeological research on 26 skeletal populations from throughout Mesoamerica dating between 600-1000 A.D. Dramatic sociopolitical and demographic shifts during this period have been inferred from archaeological and ethnohistoric data, but there is currently no consensus regarding the nature of interaction between the sub-regions of Mesoamerica. The study is not specifically concerned with the cause of these shifts, but rather with whether or not any demographic shifts that may have occurred can be detected biologically through the analysis of dental variation. Historically, researchers have hypothesized that populations from Central Mexico migrated south into the Maya region at various times during the Classic and Postclassic periods. Although there is significant debate over the degree of influence that central Mexico exercised throughout Mesoamerica, most assume that migration did occur and that archaeological evidence of contact indicates the movement of populations. Despite the perceived importance of the Maya-Mexican relationship to Mesoamerican prehistory, this will be the first bioarchaeological study of sufficient scale to help resolve this issue. The inclusion of materials from all over Mesoamerica in a single study is essential to answer the research questions posed in the study. The scope of the study will allow for the detection of changes in population structure through time and for the isolation of sources of gene flow into the Maya area from outside. Of particular importance is the isolation of particular sites within each sub-region that preferentially interacted with sites outside of their respective area. The specific tasks of the research are 1) to assess the biological distance of sites within each of the three sub-regions to detect outliers; 2) to calculate levels of genetic heterozygosity for each sub-region and compare individual sites to these expected values, 3) to compare the biological distance of specific sites within each sub-region that exhibit greater than expected levels of genetic heterozygosity. The identification of spheres of interaction between specific sites from different sub-regions that deviate from what is expected will help illuminate the nature of central Mexican influence in the Maya area. The project is unique in being the largest study of biological affinity in Mesoamerica using both metric and non-metric dental data, and the first to record cemento-enamel junction (CEJ) and crown measurements on all individuals. The intellectual merits of the study stem from its contribution to advance our current understanding of pan-regional interaction in Mesoamerica, as well as adding to the current literature on the agreement between crown and CEJ measurements.The broader impacts of the project are its contribution to research on an important period of Mesoamerican history. Additionally, researchers will be able to access raw, not summary data, from approximately 3,500 individuals for comparison with their own data or for additional statistical applications of these data.