Analysis of ancient DNA, that is, leftover DNA from long-dead organisms, is a new and exciting area of research. It can give key insights to the history of human, animal, or plant migrations, the diets of ancient organisms, changing microbial diversity, and more. The method is frought with difficulties, mostly related to procurring and analyzing samples free of contamination. Because DNA breaks down over time, the amount of aDNA is relatively small, especially relative to all the potential sources of DNA contamination (for example from your hands, airborn dust and microbes, microbes living next to your environmental sample, etc.)
This spring the Brown University-Marine Biological Laboratory IGERT class set out to analyze aDNA in a sediment core from lovely Siders Pond, Falmouth, MA. This is a pond I have sampled multiple times during my time working at MBL and for the Semester of Environmental Science. It is a meromictic pond, somewhat brackish at the surface and quite salty in the hypolimnion (it receives Atlantic Ocean water during high tides and storms). The pond is in downtown Falmouth and is thought to have undergone significant changes during the course of Falmouth’s growth. The IGERT class wanted to test this using aDNA. The plan is to take a sediment core, generate an age model chronology for the sediment, and assess what types of organism turnover and diversity changes have occurred through time.
Here are pictures from our coring day. Data is so far unavailable.