Doctoral Dissertation Improvement: Assessing the Demographic and Genetic Impact of Major Social Transitions in Historical Perspective

理解人类种群遗传多样性的一个重大科学问题是，现代多样性是如何受到社会文化转型和人类历史上其他重大事件的影响的。这些因素及其后果还没有被很好地理解，尽管人类群体的基因构成有可能发生重大改变。这篇论文由博士生Jaime Mata-Miguez(在德克萨斯大学奥斯汀分校Deborah Bolnick博士的指导下)研究了文化扩张和殖民主义对人类群体遗传学的人口和遗传影响，调查了社区重组、迁徙模式改变和/或战争和其他形式的改变或破坏的传统生活方式导致的死亡率上升等因素如何在受影响的人类群体中产生深刻的遗传影响。为了全面解决这一研究问题，该项目必须关注一个人类研究群体，该群体既有这些历史影响的数据，也有该群体古代和现代成员的基因构成的数据。通过比较古人类遗骸和墨西哥萨尔托坎现代居民的DNA，可以评估与阿兹特克帝国扩张和西班牙在中美洲的殖民主义相关的多重社会影响造成的基因变化。这是检验前面讨论的影响的一个独特的测试案例；哈尔托坎的考古研究已经发掘出保存完好的DNA的前阿兹特克人和阿兹特克人的遗骸，因此，哈尔托坎为研究阿兹特克扩张时期的基因变化提供了一个独特的机会，而这些前西班牙裔样本与现代居民之间的基因比较也使人们有可能澄清西班牙殖民主义开始后，哈尔托坎发生的基因变化。作为第一个从单一地点分析古代和现代样本中全基因组标记的项目，这项研究将极大地增加推断过去人口历史的统计能力，并阐明除了遗传漂移和基因流动等因素外，重大社会动荡如何影响我们的遗传学。该项目还有助于产生一系列更广泛的科学和社会影响。通过比较古代和现代来自萨尔托坎的DNA，这项调查阐明了社会文化变化的遗传后果，并展示了重大历史事件如何塑造了近代人类的遗传多样性。遗传数据和结果正通过公共数据库、同行评议出版物、科学介绍、大众媒体文章和教育介绍向哈尔托坎人社区传播，增进科学理解和欣赏，同时促进这些数据对其他相关研究的附加值。社区协作和参与是这一项目的重要组成部分，它促进公众参与科学，并促进土著社区的科学素养。最后，这项研究为德克萨斯大学奥斯汀分校的研究生和本科生提供了研究、培训和指导机会，包括增加代表不足的群体成员对科学的参与。

A major scientific question in the understanding of human population genetic diversity is how modern diversity has been shaped by sociocultural transitions and other major events in human history. These factors and their consequences are not well-understood, despite the potential for significant reshaping of the genetic makeup of human populations. This dissertation research by doctoral student Jaime Mata-Miguez (under the supervision of Dr. Deborah Bolnick, University of Texas at Austin) examines the demographic and genetic impact of cultural expansion and colonialism on human population genetics, investigating how factors such as community reorganization, altered migration patterns, and/or increasing mortality rates resulting from warfare and other forms of changed or destroyed traditional lifeways can produce profound genetic effects in impacted human populations.To comprehensively address this research question, the project must focus on a human study population for which there are data on both these historical impacts and the genetic makeup of the ancient and present-day members of that population. By comparing DNA from ancient human remains and the present-day inhabitants of Xaltocan, Mexico, the genetic changes resulting from the multiple societal impacts associated with expansion of the Aztec empire and Spanish colonialism in Mesoamerica can be assessed. This is a unique test case for examining the impacts previously discussed; archaeological research at Xaltocan has unearthed both pre-Aztec and Aztec human remains with well-preserved DNA, so Xaltocan offers a unique opportunity to study genetic changes across the period of Aztec expansionism, while genetic comparisons between these pre-Hispanic samples and the modern residents also make it possible to clarify the genetic changes that occurred at Xaltocan after the onset of Spanish colonialism. As the first project to analyze genome-wide markers in both ancient and modern samples from a single location, the research will dramatically increase statistical power to infer past population history and to clarify how major societal disruptions impact our genetics, in addition to forces such as genetic drift and gene flow. This project also contributes to an array of broader scientific and social impacts. By comparing ancient and modern DNA from Xaltocan, this investigation elucidates the genetic consequences of sociocultural change and shows how major historical events have shaped human genetic diversity in recent times. Genetic data and results are being disseminated through public databases, peer-reviewed publications, scientific presentations, articles in the popular press, and educational presentations to the Xaltocan community, enhancing scientific understanding and appreciation while contributing to the added value of these data for additional relevant research. Community collaboration and participation is a critical part of this project, fostering public engagement with science and promoting scientific literacy in indigenous communities. Finally, this study provides research, training, and mentorship opportunities for graduate and undergraduate students at the University of Texas at Austin, including increased participation of members of under-represented groups in science.