Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Bacteriol. 2008 Jul;190(14):5087-94. doi: 10.1128/JB.01976-07. Epub 2008 May 16.

Impact of individual mutations on increased fitness in adaptively evolved strains of Escherichia coli.

Author information

  • 1Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, California 92093-0412, USA. palsson@ucsd.edu.

Abstract

We measured the relative fitness among a set of experimentally evolved Escherichia coli strains differing by a small number of adaptive mutations by directly measuring allelic frequencies in head-to-head competitions using a mass spectrometry-based method. We compared the relative effects of mutations to the same or similar genes acquired in multiple strains when expressed in allele replacement strains. We found that the strongest determinant of fitness among the evolved strains was the impact of beneficial mutations to the RNA polymerase beta and beta' subunit genes. We also identified several examples of epistatic interactions between rpoB/C and glpK mutations and identified two other mutations that are beneficial only in the presence of previously acquired mutations but that have little or no adaptive benefit to the wild-type strain. Allele frequency estimation is shown to be a highly sensitive method for measuring selection rates during competitions between strains differing by as little as a single-nucleotide polymorphism and may be of great use for investigating epistatic interactions.

PMID:
18487343
[PubMed - indexed for MEDLINE]
PMCID:
PMC2447027
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk