Stability and fate of environmental DNA

Abstract

Stability and fate of environmental DNA Hannah Kleyer and Kristy Deiner Environmental DNA Group, Swiss Federal Institute of Technology (ETH) Zürich, Switzerland Environmental DNA (eDNA) has become a crucial tool to detect organism distribution and monitor biodiversity in various environments. eDNA is shed into the environment by animals and plants as complex mixture of different states ranging from intact cells and organelles, to lysed cells releasing dissolved DNA. Yet, the dynamics and mechanisms of eDNA persistence are largely unknown especially when considering different eDNA states. This is decisive in advancing eDNA data interpretation since each one of these states can potentially have a different decay rate leading to a different persistence time in the environment. We experimentally evaluated degradation of plant and animal eDNA from cells, organelles and in its dissolved form under precisely controlled conditions with and without bacteria. We hypothesize that eDNA decay depends on its state and that dissolved DNA degrades faster than organelle or cellular DNA. Moreover, we expect increased eDNA degradation in presence of bacteria using nucleic acid as nutrient source. First results show clear effects from presence of bacteria on the experimental conditions. Bacterial presence leads to a decrease in pH overtime in replicates containing cells, organelles and when all states were mixed, but not for dissolved DNA alone, suggesting increased metabolic activity when other cellular components are also available affecting eDNA decay.