Doctoral Dissertation Improvement Award: DNA Analysis As A Tool For Understanding Population Movement

考古学中对移民的研究主要集中在其作为文化变革代理人的作用上。然而，迁移和遗传混合也是生物变化和适应的驱动因素。因此，描述古代迁徙如何塑造遗传多样性对于了解混合人群的生物祖先、文化进化和健康结果至关重要。但是，由于现代人群并没有保留古代群体的所有基因组多样性，对当代个体的基因研究为重建古代人口统计事件提供了有限的解决方案。这个限制可以通过结合考古问题和古代DNA来解决。这项调查描述了古代人类群体的遗传多样性特征，并测试了关于他们与其他古代和现代人群关系的假设。具体来说，从三个考古遗址（Tibes， Punta Candelero和Paso del Indio）的人类骨骼遗骸中获得的古代DNA将被分析，以调查来自加勒比海波多黎各岛的前哥伦比亚人口的迁移和遗传混合在历史中的作用。该项目包括对本科生进行实验室和分析方法的培训，并通过培训一名波多黎各女博士生，促进代表性不足的群体参与科学。研究人员将通过面向学生、教师和公众的在线资源Ask-A Biologist传播项目发现，并与考古学家和Tibes遗址博物馆礼仪中心合作，将发现整合到公共遗址参观中，从而吸引公众参与。本研究的一个重要方面是从退化的骨骼遗骸DNA恢复方案的优化。这种方法的发展提高了从热带环境中遗骸中恢复古代DNA的能力，并可扩展到法医应用，在法医应用中，DNA可能由于尸体在不利的保存环境中沉积而受损。关于古代有多少移民定居在波多黎各岛，他们来自哪里，以及这些过程如何影响古代加勒比盆地的社会互动网络，争论仍然存在。这项研究将从公元500-1300年的骨骼遗骸中提取的古代线粒体和核DNA与其他现代和古代美洲土著人口的数据进行了比较，以确定：(1)波多黎各的古代人口与美洲大陆土著群体有何关系，这可能表明他们的起源是什么？(2)在接触前的加勒比海地区，基因流动的程度如何？这可能表明当地的社会互动如何？项目结果重新评估了波多黎各和加勒比地区现有的人口模型，并探讨了移民和混合如何塑造了古代加勒比人口的生物文化多样性。通过考察岛屿间迁移和基因交换的程度，这项调查阐明了亲属关系、居住模式和流动性在维持前哥伦布时期加勒比地区相互作用网络中的作用。最后，这项研究还揭示了前哥伦比亚人口和现代波多黎各人之间的遗传关系，波多黎各人是美国第二大西班牙裔群体。鉴于美洲土著族裔在当代波多黎各文化中所起的作用越来越大，项目结果对现代波多黎各身份的建构和经验具有影响。

Research on migration in Archaeology has largely focused on its role as an agent of cultural change. However, migration and genetic admixture are also drivers of biological change and adaptation. Consequently, characterizing how ancient migrations shape genetic diversity is vital to inform understanding of biological ancestry, cultural evolution, and health outcomes in admixed human populations. But, because modern populations do not retain all the genomic diversity of ancient groups, genetic research with contemporary individuals provides limited resolution for reconstructing ancient demographic events. This limitation can be addressed by combining archaeological questions with ancient DNA. This investigation characterizes the genetic diversity of ancient human groups and test hypotheses about their relationships to other ancient and modern populations. Specifically, ancient DNA obtained from human skeletal remains in three archaeological sites (Tibes, Punta Candelero and Paso del Indio) will be analyzed to investigate the role of migration and genetic admixture in the history of pre-Columbian populations from the Caribbean island of Puerto Rico. The project incorporates training of undergraduate students in laboratory and analytical methods and contributes to the participation of underrepresented groups in the sciences through training of a female, Puerto Rican doctoral student. The researchers will engage the public by disseminating project findings through Ask-A Biologist, an online resource for students, teachers and the public, and by collaborating with archaeologists and the Ceremonial Center of Tibes site museum to integrate findings in public site tours. A significant aspect of this research is the optimization of protocols for DNA recovery from degraded skeletal remains. This methodological development improves ancient DNA recovery from remains in tropical environments, and can be extended to forensic applications where DNA may be damaged due to corpse deposition in adverse preservation contexts. Debate remains about how many migrants settled the island of Puerto Rico in antiquity, where they came from, and how these processes influenced social interaction networks across the ancient Caribbean basin. This investigation compares ancient mitochondrial and nuclear DNA from skeletal remains dated A.D. 500-1300, with data from other modern and ancient indigenous populations of the Americas to determine: (1) How were ancient populations in Puerto Rico related to continental Native American groups, and what may this indicate about their origins? (2) What was the extent of gene flow in the pre-contact Caribbean, and what may this indicate about local social interaction? Project findings reassess existing models for the peopling of Puerto Rico and the Caribbean, and explore how migration and admixture shaped the biocultural diversity of ancient Caribbean populations. By also examining the extent of inter-island migration and genetic exchange, this investigation elucidates the role of kinship, residence patterns and mobility in the maintenance of interaction networks across the pre-Columbian Caribbean. Lastly, this study also sheds light on the genetic relationships between pre-Columbian populations and modern Puerto Ricans, the second largest Hispanic group in the USA. Given the growing role that Native American ethnicity plays in contemporary Puerto Rican culture, project results have implications for the construction and experience of modern Puerto Rican identity.