Escherichia coli Long-Term Evolution Experiment, Ara-3 Isolate Sequencing

The genomes of twenty additional strains isolated from population Ara-3 of the Lenski long-term evolution experiment with E. coli were sequenced. This population evolved a key innovation, aerobic citrate utilization, after 15 years of laboratory evolution. These new genomes were sequenced to refine the phylogeny of strains that evolved in this population in order to understand the series of mutations that led to the first appearance of the new Cit+ phenotype and to determine why this innovation was such a rare event.