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

考古学对迁徙的研究主要集中在它作为文化变革推动者的作用上。然而，迁徙和遗传混合也是生物变化和适应的驱动因素。因此，表征古代迁徙如何塑造遗传多样性，对于了解混杂人类的生物祖先、文化进化和健康结果至关重要。但是，由于现代人口并没有保留古代群体的所有基因组多样性，当代个体的基因研究为重建古代人口事件提供了有限的分辨率。这一局限可以通过将考古学问题与古代DNA相结合来解决。这项调查描述了古人类群体的遗传多样性，并检验了关于他们与其他古代和现代群体关系的假设。具体地说，将分析从三个考古遗址(Tibes、Punta Candelero和Paso del Indio)的人类骨骼遗骸中获得的古代DNA，以调查移民和基因混合在加勒比海波多黎各岛上的前哥伦布人历史上的作用。该项目包括对本科生进行实验室和分析方法方面的培训，并通过培训一名波多黎各女博士生，促进人数不足的群体参与科学。研究人员将通过学生、教师和公众在线资源Ask-A生物学家传播项目成果，并与考古学家和泰伯斯遗址博物馆仪式中心合作，将这些发现整合到公共遗址参观中。这项研究的一个重要方面是优化从降解的骨骼残骸中提取DNA的方案。这一方法的发展改进了从热带环境中的遗骸中恢复古代DNA，并可扩展到法医应用，在不利的保存环境中，由于身体沉积，DNA可能会损坏。关于古代有多少移民在波多黎各定居，他们来自哪里，以及这些过程如何影响整个古老的加勒比海盆地的社会互动网络，仍然存在争议。这项调查将公元500年至1300年的骨骼遗骸中的古代线粒体和核DNA与美洲其他现代和古代土著居民的数据进行比较，以确定：(1)波多黎各古代人口与美洲大陆土著群体是如何联系的，这可能表明他们的起源是什么？(2)在接触之前的加勒比海地区，基因流动的程度如何，这可能表明当地的社会互动？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式，并探讨了移民和混居如何塑造了古代加勒比人口的生物文化多样性。通过审查岛屿间移徙和遗传交流的程度，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加勒比地区互动网络方面的作用。最后，这项研究还揭示了前哥伦布人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拉美裔群体。鉴于美洲原住民在当代波多黎各文化中发挥的作用越来越大，项目结果对现代波多黎各人身份的构建和体验具有影响。

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.