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

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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.