Doctoral Dissertation Improvement: If and How Many "Races"? The Application of Mixture Modeling to World-Wide Craniometric Variation

博士论文改进：是否以及有多少次“竞赛”？

• 批准号: 0823489
• 负责人: Lyle Konigsberg
• 金额: $ 1.3万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0823489&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; How; Many

The classification of modern humans into categories using phenotypic traits has experienced a lengthy and complex history in biological anthropology. While understanding the patterns of human biological variation is essential to revealing population structure, demographic history and the trajectory of modern human evolution, such categorization, even if based on biological differences, is contentious given its past association with concepts of "race" and related ideological agendas. Within physical anthropology, criticisms of the "race concept" and anxieties over scientific racism have generated concerns regarding the validity of any study that uses morphological variation as a way to explore evolutionary relationships among human groups. It is argued that any biological information captured by concepts of "race", "ethnicity" or "geographic ancestry" is necessarily confounded by personal beliefs and flawed methodologies and that, in turn, it is impossible to achieve an unbiased explanation of human variation. A tension exists, therefore, between those biological anthropologists who use craniometric variation as a means to access past population structure in phenotypic distance studies or to estimate individual ancestry in forensic contexts, and those who associate any discussions of group differentiation with racial typing. New genetic research on the interaction between culture and biology suggests, however, that there are alternative methods that can be explored in skeletal studies for scientifically detecting group differences and determining the statistical and practical significance of demographic information. Recent genomic work has successfully applied model based clustering to autosomal microsatellite loci in large, world-wide samples, and has identified clusters which closely corresponded to major geographic regions, ethno-culturally identifiable groups, and even admixed populations. These results show the feasibility of population classification by continental ancestry as well as the importance of "race", "ethnicity" and "ancestry" information to studies of population structure. The central question remains therefore: can similar nested hierarchical sub-structuring, or "population clusters", be revealed from phenotypic, and specifically, craniometric data using modern human samples? This project applies model based clustering, geometric morphometry, and traditional multivariate statistics to the W.W. Howells and T. Hanihara world-wide craniometric datasets and large Medieval Danish cemetery samples from the Anthropological Data Base Odense University (ADBOU) collection. Traditional linear measurements, trussed inter-landmark distance values, and three-dimensional coordinate data are used (1) to test the efficacy of these new and potentially more powerful quantitative approaches to understanding population-based differences in craniofacial shape and (2) to investigate the statistical significance of among and within-group discrimination using craniofacial measurements. This project also explores the evidentiary relevance of estimating "geographic ancestry" and its relationship to "race" using craniometrics in forensic and medico-legal contexts and the practical value of the classification results produced given current Daubert standards for expert testimony with the addition of modern American samples drawn from the University of Tennessee's Forensic Anthropology Data Bank (FDB) and demographics from the United States Census 2000.The association of clusters with geographic regions, ethno-cultural groups, and admixed populations has significant disciplinary and socio-political implications. This research will demonstrate the potential of population classification by continental ancestry and weigh the importance of "race", "ethnicity" and "ancestry" information to studies of population structure. It will also provide recommendations for improved statistical methodologies for geographic ancestry estimation and for the evidentiary significance of estimating ancestry in forensic anthropological and medico-legal contexts given current Daubert standards for scientific evidence. The craniofacial measurements obtained for this study will offer an opportunity to address questions of human biological variation, and specifically the quantification of world-wide craniometric diversity. In testing the statistical effects of combining mixture modeling with traditional and geometric morphometrics and the applicability of clustering algorithms to questions of among and within-population classification, this research will contribute to quantitative applications in anthropology. Moreover, in making new three-dimensional craniometric information from the Anthropological Data Base Odense University (ADBOU) collection available for future morphometric research, this project will not only advance the broader study of "shape" but will also increase our knowledge of the life history of these past Danish peoples, thus facilitating studies in areas of concern to skeletal biologists, population geneticists, bioarchaeologists and demographers alike and supporting additional inter-collegiate collaborations. As the raw data and the statistical computer code written for this study will be made freely accessible to other scholars, this project will encourage future researchers to investigate the methodology here employed (therefore prompting refinements to the theories addressed by this project and improvements to our scientific methods) and bring new and different questions to bear on the resources that made this project possible.

使用表型特征对现代人类进行分类在生物人类学中经历了漫长而复杂的历史。虽然了解人类生物变异的模式对于揭示人口结构、人口历史和现代人类进化轨迹至关重要，但这种分类，即使是基于生物学差异，也存在争议，因为它过去与“种族”概念和相关意识形态议程相关。在体质人类学中，对“种族概念”的批评和对科学种族主义的焦虑引起了人们对任何使用形态变异作为探索人类群体之间进化关系的方法的研究的有效性的担忧。有人认为，“种族”、“族裔”或“地理血统”概念所捕获的任何生物信息必然会受到个人信仰和有缺陷的方法论的混淆，反过来，不可能对人类变异做出公正的解释。因此，生物人类学家和那些将群体分化的讨论与种族分型联系起来的生物人类学家之间存在着紧张关系，这些生物人类学家在表型距离研究中使用颅骨测量变异作为了解过去人口结构或在法医学背景下估计个体血统的手段。然而，关于文化和生物学之间相互作用的新遗传学研究表明，在骨骼研究中可以探索其他方法，以科学地检测群体差异并确定人口统计信息的统计和实际意义。 最近的基因组工作已成功地将基于模型的聚类应用于大型全球样本中的常染色体微卫星基因座，并确定了与主要地理区域、民族文化可识别群体甚至混合人群密切对应的聚类。这些结果显示了按大陆血统对人口进行分类的可行性以及“种族”、“族裔”和“血统”信息对人口结构研究的重要性。因此，核心问题仍然是：是否可以使用现代人类样本从表型数据（特别是颅骨测量数据）中揭示类似的嵌套分层子结构或“群体集群”？该项目将基于模型的聚类、几何形态测量和传统的多元统计应用于 W.W. Howells 和 T. Hanihara 来自欧登塞大学人类学数据库 (ADBOU) 收藏的全球颅骨测量数据集和大型中世纪丹麦墓地样本。使用传统的线性测量、桁架式地标间距离值和三维坐标数据（1）来测试这些新的、可能更强大的定量方法在理解基于人群的颅面形状差异方面的有效性；（2）使用颅面测量来研究群体间和群体内歧视的统计显着性。该项目还探讨了在法医和医学法律背景下使用颅骨测量学估计“地理血统”及其与“种族”关系的证据相关性，以及根据当前专家证词多伯特标准产生的分类结果的实用价值，并添加了从田纳西大学法医人类学数据库（FDB）提取的现代美国样本和来自美国人口普查的人口统计数据 2000.集群与地理区域、民族文化群体和混合人口的联系具有重大的学科和社会政治影响。这项研究将展示按大陆血统进行人口分类的潜力，并权衡“种族”、“民族”和“血统”信息对人口结构研究的重要性。它还将为改进地理血统估计的统计方法以及考虑到当前多伯特科学证据标准的法医人类学和医学法律背景下估计血统的证据意义提供建议。本研究获得的颅面测量结果将为解决人类生物变异问题，特别是全球颅面多样性的量化问题提供机会。在测试混合建模与传统几何形态计量学相结合的统计效果以及聚类算法对群体间和群体内分类问题的适用性时，这项研究将有助于人类学的定量应用。此外，通过将欧登塞大学人类学数据库（ADBOU）收集的新的三维颅骨测量信息用于未来的形态测量研究，该项目不仅将推进对“形状”的更广泛研究，还将增加我们对这些过去丹麦人的生活史的了解，从而促进骨骼生物学家、群体遗传学家、生物考古学家和人口统计学家等关注领域的研究，并支持更多 校际合作。由于为本研究编写的原始数据和统计计算机代码将免费提供给其他学者，该项目将鼓励未来的研究人员调查这里所采用的方法（从而促进该项目所讨论的理论的完善和我们的科学方法的改进），并为使该项目成为可能的资源带来新的和不同的问题。