The role of transient hypermutators in adaptive mutation in Escherichia coli
AUTOR(ES)
Rosche, William A.
FONTE
The National Academy of Sciences
RESUMO
Microbial populations under nonlethal selection can give rise to mutations that relieve the selective pressure, a phenomenon that has come to be called “adaptive mutation.” One explanation for adaptive mutation is that a small proportion of the cells experience a period of transient hypermutation, and that these hypermutators account for the mutations that appear. The experiments reported here investigated the contribution that hypermutators make to the mutations occurring in a Lac− strain of Escherichia coli during selection for lactose utilization. A broad mutational screen, loss of motility, was used to compare the frequency of nonselected mutations in starved Lac− cells, in Lac+ revertants, and in Lac+ revertants carrying yet another nonselected mutation. These frequencies allowed us to calculate that the hypermutating subpopulation makes up ≈0.06% of the population and that its mutation rate is elevated ≈200-fold. From these numbers we conclude that the hypermutators are responsible for nearly all multiple mutations but produce only ≈10% of the adaptive Lac+ mutations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=22007Documentos Relacionados
- Adaptive Mutation in Escherichia coli
- Rebuttal: Adaptive Mutation in Escherichia coli (Foster)
- Rebuttal: Adaptive Mutation in Escherichia coli (Foster)
- Error-Prone Polymerase, DNA Polymerase IV, Is Responsible for Transient Hypermutation during Adaptive Mutation in Escherichia coli
- Adaptive Reversion of a Frameshift Mutation in Escherichia Coli
