Studying Past Ecosystems and Human Behaviors Using Environmental and Ancient DNA
Isolating and studying degraded DNA from preserved organismal remains and environmental samples allows new inferences about past ecosystem compositions, population dynamics, and, in the context of archaeological remains, human interactions with their environment. In this dissertation, I addressed how sequencing depth and stochasticity of metabarcoding PCR influences various measures of biodiversity. I found that sequencing depth and stochasticity between PCR replicates significantly influence estimates of alpha but not beta diversity. In my second chapter, I used eDNA isolated from permafrost cores spanning the last 50,000 years in the Klondike, Canada to characterize community composition and turnover of plant and mammalian communities. In this chapter, I characterized floral and faunal change over the last 50,000 years, with clear shifts from steppe to boreal forest habitat delineated with the presence and absence of arctic ground squirrels and woody plants. Finally, I isolated ancient DNA from archaeological moccasins to observe hunting patterns of Bison used by occupants of the Promontory Caves of Utah, an archaeological site occupied 1240-1290 AD. I found the majority (87%) of moccasins were constructed from female bison, supporting prior hypotheses of hunting strategies targeting cow-calf herds at the end of fall preparing for overwintering. My dissertation highlights some of the many questions that degraded DNA present in soil, bone, and preserved hides can contribute towards answering.