scholarly journals The effect of population bottlenecks on mutation rate evolution in asexual populations

2013 ◽  
Vol 27 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Y. Raynes ◽  
A. L. Halstead ◽  
P. D. Sniegowski
Keyword(s):  
Mutation Rate ◽  
Population Bottlenecks ◽  
Asexual Populations ◽  
Mutation Rate Evolution

scholarly journals The Evolution of Mutation Rate in Finite Asexual Populations

Genetics ◽  
2005 ◽  
Vol 172 (1) ◽  
pp. 611-626 ◽  
Author(s):  
Jean-Baptiste André ◽  
Bernard Godelle
Keyword(s):  
Mutation Rate ◽  
Asexual Populations

scholarly journals The evolution of bacterial mutation rates under simultaneous selection by interspecific and social parasitism

2013 ◽  
Vol 280 (1773) ◽  
pp. 20131913 ◽  
Author(s):  
Siobhán O'Brien ◽  
Antonio M. M. Rodrigues ◽  
Angus Buckling
Keyword(s):  
Mutation Rate ◽  
Social Parasitism ◽  
Mutation Rates ◽  
Bacterial Populations ◽  
Simultaneous Selection ◽  
Bacterial Mutation ◽  
Selection For ◽  
Intraspecific Parasitism ◽  
Theory And Experiments ◽  
Mutation Rate Evolution

Many bacterial populations harbour substantial numbers of hypermutable bacteria, in spite of hypermutation being associated with deleterious mutations. One reason for the persistence of hypermutators is the provision of novel mutations, enabling rapid adaptation to continually changing environments, for example coevolving virulent parasites. However, hypermutation also increases the rate at which intraspecific parasites (social cheats) are generated. Interspecific and intraspecific parasitism are therefore likely to impose conflicting selection pressure on mutation rate. Here, we combine theory and experiments to investigate how simultaneous selection from inter- and intraspecific parasitism affects the evolution of bacterial mutation rates in the plant-colonizing bacterium Pseudomonas fluorescens. Both our theoretical and experimental results suggest that phage presence increases and selection for public goods cooperation (the production of iron-scavenging siderophores) decreases selection for mutator bacteria. Moreover, phages imposed a much greater growth cost than social cheating, and when both selection pressures were imposed simultaneously, selection for cooperation did not affect mutation rate evolution. Given the ubiquity of infectious phages in the natural environment and clinical infections, our results suggest that phages are likely to be more important than social interactions in determining mutation rate evolution.

scholarly journals Mutation-selection balance and the evolutionary advantage of sex and recombination

1990 ◽  
Vol 55 (3) ◽  
pp. 199-221 ◽  
Author(s):  
Brian Charlesworth
Keyword(s):  
Mutation Rate ◽  
Genetic Recombination ◽  
Random Mating ◽  
Quantitative Character ◽  
Sexual Population ◽  
Evolutionary Advantage ◽  
Diminishing Returns ◽  
Mean Fitness ◽  
Locus System ◽  
Asexual Populations

SummaryMutation-selection balance in a multi-locus system is investigated theoretically, using a modification of Bulmer's infinitesimal model of selection on a normally-distributed quantitative character, taking the number of mutations per individual (n) to represent the character value. The logarithm of the fitness of an individual with n mutations is assumed to be a quadratic, decreasing function of n. The equilibrium properties of infinitely large asexual populations, random-mating populations lacking genetic recombination, and random-mating populations with arbitrary recombination frequencies are investigated. With ‘synergistic’ epistasis on the scale of log fitness, such that log fitness declines more steeply as n increases, it is shown that equilibrium mean fitness is least for asexual populations. In sexual populations, mean fitness increases with the number of chromosomes and with the map length per chromosome. With ‘diminishing returns’ epistasis, such that log fitness declines less steeply as n increases, mean fitness behaves in the opposite way. Selection on asexual variants and genes affecting the rate of genetic recombination in random-mating populations was also studied. With synergistic epistasis, zero recombination always appears to be disfavoured, but free recombination is disfavoured when the mutation rate per genome is sufficiently small, leading to evolutionary stability of maps of intermediate length. With synergistic epistasis, an asexual mutant is unlikely to invade a sexual population if the mutation rate per diploid genome greatly exceeds unity. Recombination is selectively disadvantageous when there is diminishing returns epistasis. These results are compared with the results of previous theoretical studies of this problem, and with experimental data.

scholarly journals Drift-barrier hypothesis and mutation-rate evolution

2012 ◽  
Vol 109 (45) ◽  
pp. 18488-18492 ◽  
Author(s):  
W. Sung ◽  
M. S. Ackerman ◽  
S. F. Miller ◽  
T. G. Doak ◽  
M. Lynch
Keyword(s):  
Mutation Rate ◽  
Mutation Rate Evolution

scholarly journals Distinct evolutionary trajectories in asexual populations through an interplay of their size, resource availability and mutation rates

2020 ◽  
Author(s):  
Bhaskar Kumawat ◽  
Ramray Bhat
Keyword(s):  
Mutation Rate ◽  
Single Cells ◽  
Maximum Size ◽  
Mutation Rates ◽  
Genome Replication ◽  
Sequence Motifs ◽  
Complex Picture ◽  
Distinct Sequence ◽  
Resource Levels ◽  
Asexual Populations

AbstractAsexually reproducing populations of single cells evolve through mutation, natural selection, and genetic drift to enhance their reproductive fitness. The environment provides the contexts that allow and regulate their fitness dynamics. In this work, we used Avida - a digital evolution framework - to uncover the effect of mutation rates, maximum size of the population, and the relative abundance of resources, on evolutionary outcomes in asexually reproducing populations of digital organisms. We observed that over extended simulations, the population evolved predominantly to one of several discrete fitness classes, each with distinct sequence motifs and/or phenotypes. For a low mutation rate, the organisms acquired either of four fitness values through an enhancement in the rate of genomic replication. Evolution at a relatively higher mutation rate presented a more complex picture. While the highest fitness values at a high mutation rate were achieved through enhanced genome replication rates, a suboptimal one was achieved through organisms sharing information relevant to metabolic tasks with each other. The information sharing capacity was vital to fitness acquisition and frequency of the genotype associated with it increased with greater resource levels and maximum population size. In addition, populations optimizing their fitness through such means exhibited a greater degree of genotypic heterogeneity and metabolic activity than those that improved replication rates. Our results reveal a minimal set of conditions for the emergence of interdependence within evolving populations with significant implications for biological systems in appropriate environmental contexts.

scholarly journals Selection on mutators is not frequency-dependent

2019 ◽  
Author(s):  
Yevgeniy Raynes ◽  
Daniel M. Weinreich
Keyword(s):  
Mutation Rate ◽  
Genetic Variants ◽  
Beneficial Mutation ◽  
Agent Based ◽  
Initial Frequency ◽  
Genome Wide ◽  
Per Capita ◽  
Asexual Populations ◽  
Probability Of Fixation ◽  
Evolutionary Fate

AbstractThe evolutionary fate of mutator mutations – i.e., genetic variants that raise the genome-wide mutation rate – in asexual populations is often described as being frequency (or number) dependent. This common intuition suggests that mutators can invade a population by hitchhiking with a sweeping beneficial mutation, but only when sufficiently frequent to produce such a mutation before non-mutators do. Here, we use stochastic, agent-based simulations to show that neither the strength nor the sign of selection on mutators depend on their initial frequency, and while the overall probability of hitchhiking increases predictably with frequency, the per-capita probability of fixation remains unchanged.

scholarly journals The effect of known mutator alleles in a cluster of clinicalSaccharomyces cerevisiaestrains

2016 ◽  
Author(s):  
Daniel A. Skelly ◽  
Paul M. Magwene ◽  
Brianna Meeks ◽  
Helen A. Murphy
Keyword(s):  
Mutation Rate ◽  
Evolutionary Theory ◽  
Phylogenetic Analyses ◽  
Mutation Rates ◽  
Genetic Modifiers ◽  
Beneficial Mutations ◽  
Mutator Allele ◽  
Genomic Mutation ◽  
Asexual Populations ◽  
The Relationship

AbstractNatural selection has the potential to act on all phenotypes, including genomic mutation rate. Classic evolutionary theory predicts that in asexual populations, mutator alleles, which cause high mutation rates, can fix due to linkage with beneficial mutations. This phenomenon has been demonstrated experimentally and may explain the frequency of mutators found in bacterial pathogens. In contrast, in sexual populations, recombination decouples mutator alleles from beneficial mutations, preventing mutator fixation. In the facultatively sexual yeastSaccharomyces cerevisiae, segregating alleles ofMLH1andPMS1have been shown to be incompatible, causing a high mutation rate when combined. These alleles had never been found together naturally, but were recently discovered in a cluster of clinical isolates. Here we report that the incompatible mutator allele combination only marginally elevates mutation rate in these clinical strains. Genomic and phylogenetic analyses provide no evidence of a historically elevated mutation rate. We conclude that the effect of the mutator alleles is dampened by background genetic modifiers. Thus, the relationship between mutation rate and microbial pathogenicity may be more complex than once thought. Our findings provide rare observational evidence that supports evolutionary theory suggesting that sexual organisms are unlikely to harbor alleles that increase their genomic mutation rate.

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