The frequency of mutators in populations of Escherichia coli

Mutat Res. 2000 Mar 14;448(1):47-55. doi: 10.1016/s0027-5107(99)00239-0.


Owing to occasional spontaneous mutations in genes encoding DNA repair, any population of a reasonable size is expected to harbor a sub-population of genetic mutators. Using a genetically modified strain of Escherichia coli K-12, we have estimated the frequency of mutators to be about 3x10(-5). By and large, this corresponds to a mutation rate from non-mutators to mutators of 5x10(-6) per bacterium per generation. Using a mutS∷Tn10 derivative as representative for mutators, we estimated the increase in mutation rates in mutators to be 19- to 82-fold, depending on the test-mutation under consideration. The load associated with this increase in mutation rate resulted in a growth inhibition of 1%. From these data, we estimated that the rate of detrimental mutations in the non-mutators to be 2x10(-4)-8x10(-4). The situations where adaptive mutations may result in an increase in the frequency of mutators are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases*
  • Bacterial Proteins / genetics*
  • Cell Division / genetics
  • Culture Media
  • DNA Repair / genetics
  • DNA-Binding Proteins*
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins*
  • Gene Frequency
  • Genetics, Population*
  • Lac Repressors
  • Lactose / metabolism
  • MutS DNA Mismatch-Binding Protein
  • Mutation*
  • Repressor Proteins / genetics
  • Selection, Genetic


  • Bacterial Proteins
  • Culture Media
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Lac Repressors
  • LacI protein, E coli
  • Repressor Proteins
  • Adenosine Triphosphatases
  • MutS DNA Mismatch-Binding Protein
  • MutS protein, E coli
  • Lactose