Costs and benefits of high mutation rates: adaptive evolution of bacteria in the mouse gut

Science. 2001 Mar 30;291(5513):2606-8. doi: 10.1126/science.1056421.


We have shown that bacterial mutation rates change during the experimental colonization of the mouse gut. A high mutation rate was initially beneficial because it allowed faster adaptation, but this benefit disappeared once adaptation was achieved. Mutator bacteria accumulated mutations that, although neutral in the mouse gut, are often deleterious in secondary environments. Consistently, the competitiveness of mutator bacteria is reduced during transmission to and re-colonization of similar hosts. The short-term advantages and long-term disadvantages of mutator bacteria could account for their frequency in nature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Adenosine Triphosphatases*
  • Animals
  • Bacterial Proteins / genetics
  • Base Pair Mismatch
  • Biological Evolution*
  • DNA Repair / genetics*
  • DNA-Binding Proteins*
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Escherichia coli / physiology*
  • Escherichia coli Proteins*
  • Feces / microbiology
  • Genes, Bacterial
  • Germ-Free Life
  • Intestines / microbiology*
  • Mice
  • Mice, Inbred C3H
  • MutS DNA Mismatch-Binding Protein
  • Mutation*


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Adenosine Triphosphatases
  • MutS DNA Mismatch-Binding Protein
  • MutS protein, E coli