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理解人类史前历史的关键组成部分。这个项目的目标是测试一种新的方法，这种方法可以阐明自然资源的可用性，以及阿拉斯加早期人类是否或如何收获资源，从而了解过去的人类行为和发展。在阿拉斯加中部，气候正在迅速变化，因为在此之前的20,000到5,000年间，世界从冰川气候条件过渡到现代气候条件。这引发了森林的扩张，猎物(如麋鹿、野牛和驼鹿)的扩张、灭绝和/或重新分布，以及鲑鱼溪流的建立。各种成熟的方法，如骨骼和植物鉴定，揭示了这种过去的资源利用，然而，在鉴定或保存这些样本方面的挑战可能会产生关于人类活动的不完整图景。从考古沉积物中提取的古代DNA可以应对这些挑战，但一年中部分时间解冻的沉积物--许多北极地区的典型沉积物--中的古代DNA的保存目前还没有测试。这个项目将评估关于古代DNA的新的和变革性的方法，这些方法可以为数千年前人类与环境之间的关系增加一个新的视角。在这项研究中，将严格分析古代DNA结果，以评估一年中四个月解冻的沉积物可能导致的保存和采样问题--这是一个尚未测试的方法学挑战。该项目团队将比较一年中约四个月解冻的考古沉积物的古代DNA结果，这些沉积物是阿拉斯加中部的典型，与已被证明保存古代DNA(湖泊沉积物)的沉积物类型进行比较，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为在阿拉斯加和北极其他地区工作的考古学家应用这种新方法来彻底改变我们对过去景观的理解和人类对这些景观的使用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.