Even a rather small population of bacteria may contain millions of cells that undergo several generations every day. As a result, bacteria can quickly evolve and adapt to their environments. In this renewal project, the investigators will propagate, monitor, preserve, and study populations of Escherichia coli while they evolve in a defined laboratory environment for five years, bringing the duration of this long-term experiment to over 60,000 cell generations. To measure the adaptation of the bacteria, the researchers allow the evolved bacteria to compete against their ancestral strain. The researchers also compare these adaptive dynamics with changes in genome sequences in order to elucidate the rates, mechanisms, and predictability of bacterial evolution.
This project offers a unique opportunity to observe and quantify the process of evolution owing to the speed with which the bacteria evolve and the careful design of this long-term experiment. At the same time, bacteria are extremely important in several respects: as essential players in ecosystem processes, as agents of disease in humans and many other species, and as workhorses in biotechnology. Therefore, in-depth knowledge about the rates, mechanisms, and outcomes of bacterial evolution has many important implications and applications for science and society. The scientific aims and findings of this on-going research project have been and will be presented to the public via outreach activities including interviews with journalists, seminars for non-specialists, and web-based presentations hosted by the NSF and other outlets. Biological samples and datasets generated by this study will continue to be shared with the scientific community, including genome sequences placed in public repositories.
