Stress-Induced Mutagenesis and Complex Adaptation

  title={Stress-Induced Mutagenesis and Complex Adaptation},
  author={Yoav Ram and Lilach Hadany},
Because mutations are mostly deleterious, mutation rates should be reduced by natural selection. However, mutations also provide the raw material for adaptation. Therefore, evolutionary theory suggests that the mutation rate must balance between adaptability – the ability to adapt – and adaptedness – the ability to remain adapted. We model an asexual population crossing a fitness valley and analyze the rate of complex adaptation with and without stress-induced mutagenesis – the increase of… 
Molecular mechanisms involved in the regulation of mutation rates in bacteria
Stress-induced mutagenesis allows rapid adaptation to complex environmental challenges without compromising the population fitness because it reduces the overall cost of a high mutation rate.
Stress-Induced Mutagenesis, Gambler Cells, and Stealth Targeting Antibiotic-Induced Evolution
Recent advances in antibiotic-induced mutagenesis that integrate how reactive oxygen species, the SOS and general stress responses, and multichromosome cells orchestrate a stress response-induced switch from high-fidelity to mutagenic repair of DNA breaks are reviewed.
Irregularities in genetic variation and mutation rates with environmental stresses.
The appearance of new mutations is determined by the equilibrium between DNA error formation and repair. In bacteria like Escherichia coli, stresses are thought shift this balance towards increased
Errors in mutagenesis and the benefit of cell-to-cell signalling in the evolution of stress-induced mutagenesis
It is shown that stress-induced mutagenesis can be disadvantageous if errors are common; and that cell-to-cell signalling can allow stress- induced Mutagenesis to be favoured by selection even when error rates are high.
A shifting mutational landscape in 6 nutritional states: Stress-induced mutagenesis as a series of distinct stress input–mutation output relationships
The results suggest that stress-induced mutagenesis is a diverse series of stress input–mutation output linkages that is distinct in every condition, and that environments influence genetic variation as well as selection.
Adaptive tuning of mutation rates allows fast response to lethal stress in Escherichia coli
The findings show how organisms balance robustness and evolvability and help explain the prevalence of hypermutation in various settings, ranging from emergence of antibiotic resistance in microbes to cancer relapses upon chemotherapy.
Stress-Induced Mutagenesis: Implications in Cancer and Drug Resistance.
Molecular mechanisms of stress-response-dependent (stress-induced) mutagenesis that occur from bacteria to cancer, and are activated by starvation, drugs, hypoxia, and other stressors are reviewed.
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 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.
Generation of Variation and Mean Fitness Increase: Necessity is the Mother of Genetic Invention
A general model of evolution under constant selection is analyzed and it is found that if a modifier allele increases the rate at which individuals of below-average fitness generate variation, then it will increase in frequency and increase the population mean fitness.


Stress-Induced Mutagenesis in Bacteria
It is suggested that irrespective of the causes of their emergence, stress-induced mutations participate in adaptive evolution and could be a by-product of genetic strategies for improving survival under stress.
Mutation as a Stress Response and the Regulation of Evolvability
The emerging commonalities in stress-induced-mutation mechanisms provide hope for new therapeutic interventions for all of these processes, including microbial pathogenesis and antibiotic-resistance, and tumor progression and chemotherapy resistance, all of which occur under stress, driven by mutations.
  • Y. RamL. Hadany
  • Biology
    Evolution; international journal of organic evolution
  • 2012
The results suggest that if beneficial mutations occur, even rarely, then stress‐induced hypermutation is advantageous for bacteria at both the individual and the population levels and that it is likely to evolve in populations of bacteria in a wide range of conditions because it is favored by selection.
Evolutionary significance of stress-induced mutagenesis in bacteria.
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.
Evolution of mutation rates in bacteria
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
The evolution of mutation rates: separating causes from consequences
The physiological cost of reducing mutation below the low level observed in most populations may be the most important factor in setting the genomic mutation rate in sexual and asexual systems, regardless of the benefits of mutation in producing new adaptive variation.
Stress-induced mutation via DNA breaks in Escherichia coli: A molecular mechanism with implications for evolution and medicine
The mechanisms of stress‐induced mutation that are being revealed experimentally in laboratory settings provide compelling models for mutagenesis that propels pathogen–host adaptation, antibiotic resistance, cancer progression and resistance, and perhaps much of evolution generally.
A paradigm for direct stress‐induced mutation in prokaryotes
Exposing H. pylori strains to reactive oxygen species and reactive nitrogen species directly resulted in elevated rates of spontaneous point mutation, deletion between direct repeats, and intergenomic recombination, providing a new paradigm for adaptation under increased selective pressures that may be present in other prokaryotes.
Mild environmental stress elicits mutations affecting fitness in Chlamydomonas
  • S. GohoG. Bell
  • Biology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2000
The most reasonable interpretation of observations is that mild stress increases the genomic rate of mutation, and this appears to be the first time that this phenomenon has been noticed in eukaryotes.