EAGER: Experiments to test potential identification biases of environmental DNA in unfrozen archaeological sediments

人类对自然资源的利用是了解人类史前历史的一个重要组成部分。该项目的目标是测试一种新的方法，这种方法可以揭示自然资源的可用性，以及阿拉斯加的早期人类是否或如何收获资源，从而了解过去人类的行为和发展。在阿拉斯加中部，在距今2万到5千年之间，随着世界从冰川气候过渡到现代气候条件，气候发生了迅速变化。这引发了森林的扩散、扩张、灭绝和/或狩猎动物（如麋鹿、野牛和驼鹿）的重新分配，以及鲑鱼流的建立。各种成熟的方法，如骨骼和植物鉴定，揭示了过去的资源利用，然而，在鉴定或保存这些样本方面的挑战可能会产生人类活动的不完整画面。从考古沉积物中提取的古代DNA可以解决这些挑战，但是在一年中部分时间不冻结的沉积物中保存古代DNA——这些沉积物是许多北极环境的典型特征——目前还没有经过测试。该项目将评估古代DNA的新方法和转型方法，这些方法可以为数千年前人类与环境之间的关系提供新的视角。在这项研究中，将对古代DNA结果进行严格分析，以评估一年中解冻4个月的沉积物可能导致的保存和采样问题——这是一种方法学上的挑战，目前尚未得到检验。该项目团队将比较一年中解冻大约四个月的考古沉积物的古代DNA结果，这是阿拉斯加中部的典型特征，与一种已被证明可以保存古代DNA的沉积物类型（湖泊沉积物），以评估这些新背景下古代DNA结果的可靠性。这个项目有可能通过将这种新方法应用于在阿拉斯加和北极其他地区工作的考古学家，彻底改变我们对过去景观和人类对这些景观的利用的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Human use of natural resources is a critical component for understanding human prehistory. The goal of this project is to test a new approach that could shed light on the availability of natural resources and whether or how early humans in Alaska harvested resources thus understanding past human behavior and development. In central Alaska, the climate was changing rapidly as the world transitioned from glacial to modern climate conditions between 20,000 and 5,000 years before present. This triggered the spread of the forest, expansion, extinction, and/or redistribution of game animals (such as elk, bison, and moose), and the establishment of salmon streams. Various well-established methods, such as bone and plant identification, shed light on this past resource use, however, challenges in the identification or preservation of these samples can yield an incomplete picture of human activity. Ancient DNA extracted from archaeological sediments can address these challenges, but the preservation of the ancient DNA in sediments that are unfrozen for part of the year - sediments that are typical of many Arctic contexts - is currently untested. This project will assess new and transformational methodologies on ancient DNA that can add a new view on the relationship between humans and their environment thousands of years ago. In this study, ancient DNA results will be rigorously analyzed to assess preservation and sampling issues that may result from sediments that are unfrozen for four months of the year - a methodological challenge that has yet to be tested. The project team will compare ancient DNA results from archaeological sediments that are unfrozen about four months of the year, which are typical of central Alaska, with a sediment type that has been shown to preserve ancient DNA (lake sediments) to assess the reliability of ancient DNA results from these new contexts. This project has the potential to revolutionize our understanding of past landscapes and human use of those landscapes by applying this new approach for archaeologists working in Alaska and other parts of the Arctic.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.