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Mutation, Selection and Genetic Interactions in Bacteria

  1. Isabel Gordo,
  2. Ana Sousa

Published Online: 19 MAY 2010

DOI: 10.1002/9780470015902.a0022175



How to Cite

Gordo, I. and Sousa, A. 2010. Mutation, Selection and Genetic Interactions in Bacteria. eLS. .

Author Information

  1. Instituto Gulbenkian de Ciência, Oeiras, Portugal

Publication History

  1. Published Online: 19 MAY 2010


Mutation is the ultimate source of genetic variation. The rate at which new mutations typically occur, their effects on fitness and the strength and type of genetic interactions between different mutations are key for understanding the evolution of any population. Estimates of these parameters in organisms such as bacteria will have a profound impact on our understanding of their biology, diversity, rate of speciation and in our health. Experimental evolution with bacteria presents us with the opportunity to directly measure these parameters and to test theoretical predictions about the genetic basis of adaptive evolution. Evidence has been increasing to support the view that bacterial adaptation can be extraordinary fast, that competition between different adaptive mutations may be pervasive in bacterial populations and that epistasis is very common and possibly biased towards antagonism in bacteria.

Key Concepts:

  • The distribution of the effects of beneficial mutations shows the relative abundance of large versus small effect mutations contributing to adaptation.

  • Clonal interference leads to the loss of beneficial mutations with small effects.

  • Interaction between different alleles implies that the fitness of a genotype is dependent on the genetic background where it arises, this is termed epistasis.

  • Adaptation by compensatory evolution is particularly important in bacteria.


  • mutation;
  • selection;
  • adaptation;
  • epistasis;
  • experimental evolution;
  • mutation rate;
  • fitness effect of mutations;
  • antibiotic resistance;
  • compensatory evolution