Send to:

Choose Destination
See comment in PubMed Commons below
Bioessays. 2013 Feb;35(2):123-30. doi: 10.1002/bies.201200150. Epub 2012 Dec 20.

Non-random mutation: the evolution of targeted hypermutation and hypomutation.

Author information

  • 1Cancer Research UK London Research Institute, London, UK.


A widely accepted tenet of evolutionary biology is that spontaneous mutations occur randomly with regard to their fitness effect. However, since the mutation rate varies along a genome and this variation can be subject to selection, organisms might evolve lower mutation rates at loci where mutations are most deleterious or increased rates where mutations are most needed. In fact, mechanisms of targeted hypermutation are known in organisms ranging from bacteria to humans. Here we review the main forces driving the evolution of local mutation rates and identify the main limiting factors. Both targeted hyper- and hypomutation can evolve, although the former is restricted to loci under very frequent positive selection and the latter is severely limited by genetic drift. Nevertheless, we show how an association of repair with transcription or chromatin-associated proteins could overcome the drift limit and lead to non-random hypomutation along the genome in most organisms.

Copyright © 2013 WILEY Periodicals, Inc.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Loading ...
    Write to the Help Desk