Evolution of mutation rates in bacteria

  title={Evolution of mutation rates in bacteria},
  author={Erick Denamur and Ivan Matic},
  journal={Molecular Microbiology},
Evolutionary success of bacteria relies on the constant fine‐tuning of their mutation rates, which optimizes their adaptability to constantly changing environmental conditions. When adaptation is limited by the mutation supply rate, under some conditions, natural selection favours increased mutation rates by acting on allelic variation of the genetic systems that control fidelity of DNA replication and repair. Mutator alleles are carried to high frequency through hitchhiking with the adaptive… 

The Evolution of Genetic Systems: The Influence of Recombination, Mutation Rate, and Mutational Load

This dissertation investigates the influence of recombination upon the evolution of mutation rates, and the properties of mutational load in evolving populations, using the tools of experimental evolution to provide the first-ever experimental demonstration of a population approaching mutation-selection balance.

Variable Mutation Rates as an Adaptive Strategy in Replicator Populations

The results show that in the short-term, highly optimized populations containing little variability respond better to environmental changes upon an increase of the mutation rate, whereas populations with a lower degree of optimization but higher variability benefit from reducing the mutations rate to adapt rapidly.

Genetic drift, selection and the evolution of the mutation rate

This work concludes that the drift-barrier hypothesis is consistent with comparative measures of mutation rates, provides a simple explanation for the existence of error-prone polymerases and yields a formal counter-argument to the view that selection fine-tunes gene-specific mutation rates.

Normal Mutation Rate Variants Arise in a Mutator (Mut S) Escherichia coli Population

Experimental evidence of evolution towards reduced mutation rates in a clinical isolate of Escherichia coli with an hyper-mutable phenotype due a deletion in a mismatch repair gene is reported, postulating that the observed reductions in mutation rate are coincidental to, rather than, the selective force responsible for this evolution.

Mutation rate variability as a driving force in adaptive evolution

The dynamics of resistance fixation in a bacterial population with variable mutation rates is investigated and it is shown that evolutionary outcomes are most sensitive to mutation rate variations when the population is subject to environmental and demographic conditions that suppress the evolutionary advantage of high-fitness subpopulations.

Mutation Rate Heterogeneity Increases Odds of Survival in Unpredictable Environments.

Accumulation of Deleterious Mutations During Bacterial Range Expansions

The results suggest that spatially expanding species are affected by deleterious mutations, leading to a drastic impairment of their evolutionary potential.

New Mutations: Condition-dependent Rates and Sex-specific Effects

The expected result is that the deleterious effects of mutations will be reduced and the eliminated individuals will be eliminated, as well as the evidence that the sex-­‐specific effects of sex-–‐specific selection can be affected.

Mutators Enhance Adaptive Micro-Evolution in Pathogenic Microbes

This review will focus on recent advances in understanding the phenotypic and genotypic changes occurring in MMR mutators in both prokaryotic and eukaryotic pathogens.

Population Heterogeneity in Mutation Rate Increases the Frequency of Higher-Order Mutants and Reduces Long-Term Mutational Load

The evidence for mutation rate heterogeneity is reviewed and its consequences are explored by extending classic population genetic models to allow an arbitrary distribution of mutation rate among individuals, either with or without inheritance.



Mutators and sex in bacteria: conflict between adaptive strategies.

It is shown by a simulation approach that even rare genetic exchanges, such as bacterial conjugation or transformation, can dramatically reduce the selection of mutators and reveal how second-order selection is unable to optimize the rate of generation of novelty.

Role of mutator alleles in adaptive evolution

Whether high mutation rates might play an important role in adaptive evolution is considered, as models of large, asexual, clonal populations adapting to a new environment show that strong mutator genes can accelerate adaptation, even if the mutator gene remains at a very low frequency.

The evolution of mutator genes in bacterial populations: the roles of environmental change and timing.

A model of the population dynamics of bacteria confronted with ever-changing environments is developed and it is demonstrated that subsequent to a shift in environmental conditions, there will be relatively long periods of time during which the mutator subpopulation can produce a beneficial mutation before the ancestral subpopulations are eliminated.

The population genetics of ecological specialization in evolving Escherichia coli populations

This work analysed the decay of unused catabolic functions in 12 lines of Escherichia coli propagated on glucose for 20,000 generations and found that antagonistic pleiotropy appears more important than mutation accumulation for the Decay of unused dogmatic functions in these populations.

Evolution of high mutation rates in experimental populations of E. coli

The rise of spontaneously originated mutators in populations of E. coli undergoing long-term adaptation to a new environment corroborate computer simulations of mutator evolution in adapting clonal populations, and may help to explain observations that associate high mutation rates with emerging pathogens and with certain cancers.

Mutators, population size, adaptive landscape and the adaptation of asexual populations of bacteria.

A model based on multiple mutations is proposed to illustrate how second-order selection can optimize population fitness when few favorable mutations are required for adaptation.

Fitness effects of advantageous mutations in evolving Escherichia coli populations.

  • M. ImhofC. Schlotterer
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2001
A novel marker system is used to trace adaptive events in an evolving Escherichia coli culture and to determine the selective advantage of those beneficial mutations and to estimate the rate of beneficial mutations to be 4 x 10(-9) per cell and generation.

Mutator dynamics in fluctuating environments

  • J. TravisE. R. Travis
  • Biology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2002
This study investigates mutator dynamics in a regularly varying environment, seeking to mimic conditions present, for example, under certain drug or pesticide regimes, and reveals that mutators of intermediate strength reach higher densities than very weak or strong mutators.


  • L. ChaoE. Cox
  • Biology
    Evolution; international journal of organic evolution
  • 1983
Compared the relative fitness of a series of bacterial clones isolated from these cultures, Atwood et al. were able to show that populations underwent a succession of clonal changes, each clonal replacement.

Escherichia coli mutators: selection criteria and migration effect.

It is concluded that in all cases, mutator gain depends directly on the ratio of bacteria carrying a beneficial mutation in mutator versus wild-type lineages.