FIG 2 .

Successive inversions in population Ara+1. (A) Optical map of the genome of the evolved clone sampled at 40,000 generations from population Ara+1 compared to the ancestor. Dark blue lines indicate NcoI restriction sites. White boxes show discrepant regions. The variously colored arrows indicate homologous regions of the two genomes with their corresponding locations in the two chromosomes. Red boxes indicate deletions. Black lines connecting the two genomes show alignment. (B) Chronology of the four inversions that occurred over evolutionary time in population Ara+1. Time points (2K, 20K, and 30K for 2,000, 20,000, and 30,000 generations, respectively) indicate the earliest detected occurrence of each inversion. “IND” indicates an inversion that was not detected in any of the evolved clones that were analyzed but which represents one of the two possible intermediate steps leading to the genome observed at 40,000 generations. The variously colored arrows are as described for panel A. Black lines indicate the inversions, with the names and locations of primers used during the PCR experiments also shown.