RT Journal Article
SR Electronic
T1 Tempo and mode of genome evolution in a 50,000-generation experiment
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 036806
DO 10.1101/036806
A1 Olivier Tenaillon
A1 Jeffrey E. Barrick
A1 Noah Ribeck
A1 Daniel E. Deatherage
A1 Jeffrey L. Blanchard
A1 Aurko Dasgupta
A1 Gabriel C. Wu
A1 Sébastien Wielgoss
A1 Stéphane Cruveiller
A1 Claudine Médigue
A1 Dominique Schneider
A1 Richard E. Lenski
YR 2016
UL http://biorxiv.org/content/early/2016/01/15/036806.abstract
AB Adaptation depends on the rates, effects, and interactions of many mutations. We analyzed 264 genomes from 12 Escherichia coli populations to characterize their dynamics over 50,0 generations. The trajectories for genome evolution in populations that retained the ancestral mutation rate fit a model where most fixed mutations are beneficial, the fraction of beneficial mutations declines as fitness rises, and neutral mutations accumulate at a constant rate. We also compared these populations to lines evolved under a mutation-accumulation regime that minimizes selection. Nonsynonymous mutations, intergenic mutations, insertions, and deletions are overrepresented in the long-term populations, supporting the inference that most fixed mutations are favored by selection. These results illuminate the shifting balance of forces that govern genome evolution in populations adapting to a new environment.