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

考古学对移民的研究主要集中在其作为文化变革的媒介的作用。然而，迁移和遗传混合也是生物变化和适应的驱动力。因此，描述古代移民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，对当代个体的遗传研究为重建古代人口统计学事件提供了有限的解决方案。这种局限性可以通过将考古学问题与古代DNA相结合来解决。这项调查描述了古代人类群体的遗传多样性，并测试了关于他们与其他古代和现代人群关系的假设。具体而言，从人类骨骼遗骸在三个考古遗址（Tibes，蓬塔Candelero和帕索德尔印第奥）获得的古代DNA将进行分析，以调查从加勒比岛屿波多黎各的前哥伦布时期人口的历史中的迁移和遗传混合的作用。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，促进代表性不足的群体参与科学。研究人员将通过Ask-A Biologist（一个面向学生、教师和公众的在线资源）传播项目研究结果，并与考古学家和提比斯遗址博物馆仪式中心合作，将研究结果融入公共遗址图尔斯之旅，从而吸引公众。这项研究的一个重要方面是从降解的骨骼遗骸中回收DNA的方案的优化。这种方法的发展提高了从热带环境中的遗骸中恢复古代DNA的能力，并且可以扩展到法医应用中，在这种应用中，DNA可能会由于在不利的保存环境中的尸体沉积而受损。关于有多少移民在古代定居在波多黎各岛，他们来自哪里，以及这些过程如何影响整个古代加勒比海盆地的社会互动网络，仍然存在争议。这项调查比较了公元500-1300年骨骼遗骸中的古代线粒体和核DNA，以及美洲其他现代和古代土著居民的数据，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？(2)在接触前的加勒比地区，基因流动的程度如何？这对当地的社会互动有何启示？项目研究结果重新评估了波多黎各和加勒比地区现有的人口模式，并探讨了移民和混合如何塑造古代加勒比人口的生物文化多样性。通过研究岛屿间迁移和遗传交换的程度，本调查阐明了亲属关系，居住模式和流动性在哥伦布发现美洲大陆前加勒比地区维持互动网络的作用。最后，这项研究还揭示了前哥伦布时期人口与现代波多黎各人（美国第二大西班牙裔群体）之间的遗传关系。鉴于美洲土著民族在当代波多黎各文化中发挥着越来越大的作用，项目结果对现代波多黎各身份的建设和体验产生了影响。

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.