RECOMBINATION-DEPENDENT MUTATION IN NONDIVIDING CELLS

Over the past 6 years an unexpected way of making mutations in bacteri a has challenged concepts of the genetic mechanisms behind evolution. Mechanistic studies of these so called 'adaptive' mutations are reveal ing a novel molecular mechanism involving DNA double-strand breaks, ge netic recombination, probable DNA polymerase errors, and the possible suspension of mismatch repair during the reversion of a lac frameshift mutation in Escherichia coli. The molecular details of this process a re altering our understanding of how mutations form in non-dividing ce lls.