Long-term dynamics of adaptation in asexual populations

Science. 2013 Dec 13;342(6164):1364-7. doi: 10.1126/science.1243357. Epub 2013 Nov 14.

Abstract

Experimental studies of evolution have increased greatly in number in recent years, stimulated by the growing power of genomic tools. However, organismal fitness remains the ultimate metric for interpreting these experiments, and the dynamics of fitness remain poorly understood over long time scales. Here, we examine fitness trajectories for 12 Escherichia coli populations during 50,000 generations. Mean fitness appears to increase without bound, consistent with a power law. We also derive this power-law relation theoretically by incorporating clonal interference and diminishing-returns epistasis into a dynamical model of changes in mean fitness over time.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Physiological*
  • Escherichia coli / genetics*
  • Escherichia coli / physiology*
  • Genetic Fitness*
  • Models, Biological
  • Reproduction, Asexual*