Adaptive mutation by deletions in small mononucleotide repeats

Science. 1994 Jul 15;265(5170):405-7. doi: 10.1126/science.8023163.


Adaptive reversion of a +1 frameshift mutation in Escherichia coli, which requires homologous recombination functions, is shown here to occur by -1 deletions in regions of small mononucleotide repeats. This pattern makes improbable recombinational mechanisms for adaptive mutation in which blocks of sequences are transferred into the mutating gene, and it supports mechanisms that use DNA polymerase errors. The pattern appears similar to that of mutations found in yeast cells and in hereditary colon cancer cells that are deficient in mismatch repair. These results suggest a recombinational mechanism for adaptive mutation that functions through polymerase errors that persist as a result of a deficiency in post-synthesis mismatch repair.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA Repair
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Exodeoxyribonuclease V
  • Exodeoxyribonucleases / genetics
  • Frameshift Mutation
  • Models, Genetic
  • Molecular Sequence Data
  • Mutation*
  • Recombination, Genetic*
  • Repetitive Sequences, Nucleic Acid*
  • Sequence Deletion*


  • Exodeoxyribonucleases
  • Exodeoxyribonuclease V