OEB Seminar Series

Richard Lenski
Michigan State University
"Dynamics of phenotypic and genomic evolution in a long-term experiment with E. coli"

Abstract: Evolution is an on-going process, one that can be studied experimentally in organisms with rapid generations.  We have watched 12 populations of Escherichia coli evolve in a simple environment for over 28 years and 65,000 generations.  The aims of this experiment are to characterize the tempo and mode of evolution, and to examine the repeatability of the phenotypic and genomic changes.  We have quantified the dynamics of adaptation by natural selection, documented many cases of parallel evolution, observed changes in the underlying mutation rate, and seen the appearance of a new metabolic function that transcends the usual definition of E. coli as a species.  We have sequenced hundreds of complete genomes to find the mutations in time-series of samples from the populations.  These genomic data provide insights into the dynamic coupling of phenotypic and genotypic evolution during periods of optimization and innovation.