Evolutionary implications of the frequent horizontal transfer of mismatch repair genes

Cell. 2000 Nov 22;103(5):711-21. doi: 10.1016/s0092-8674(00)00175-6.


Mutation and subsequent recombination events create genetic diversity, which is subjected to natural selection. Bacterial mismatch repair (MMR) deficient mutants, exhibiting high mutation and homologous recombination rates, are frequently found in natural populations. Therefore, we have explored the possibility that MMR deficiency emerging in nature has left some "imprint" in the sequence of bacterial genomes. Comparative molecular phylogeny of MMR genes from natural Escherichia coli isolates shows that, compared to housekeeping genes, individual functional MMR genes exhibit high sequence mosaicism derived from diverse phylogenetic lineages. This apparent horizontal gene transfer correlates with hyperrecombination phenotype of MMR-deficient mutators. The sequence mosaicism of MMR genes may be a hallmark of a mechanism of adaptive evolution that involves modulation of mutation and recombination rates by recurrent losses and reacquisitions of MMR gene functions.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases*
  • Alleles
  • Bacterial Proteins / genetics
  • Base Pair Mismatch*
  • DNA Repair*
  • DNA-Binding Proteins*
  • Escherichia coli / genetics
  • Escherichia coli Proteins*
  • Evolution, Molecular*
  • Exodeoxyribonuclease V
  • Exodeoxyribonucleases / genetics
  • Genotype
  • MutL Proteins
  • MutS DNA Mismatch-Binding Protein
  • Mutation
  • Phenotype
  • Phosphoric Monoester Hydrolases / genetics
  • Phylogeny
  • Polymerase Chain Reaction
  • Pyrophosphatases
  • Recombination, Genetic
  • Salmonella typhimurium / genetics


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • MutL protein, E coli
  • Exodeoxyribonucleases
  • Exodeoxyribonuclease V
  • Phosphoric Monoester Hydrolases
  • Adenosine Triphosphatases
  • Pyrophosphatases
  • mutT protein, E coli
  • MutL Proteins
  • MutS DNA Mismatch-Binding Protein
  • MutS protein, E coli