The effect of spontaneous mutations on competitive ability

Schaack, Sarah; Allen, Desiree E.; Latta, Leigh C.; Morgan, Kendall; Lynch, Michael

doi:10.1111/jeb.12058

Cited by 22 publications

(22 citation statements)

References 45 publications

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“…Mutations causing a .10% decline in fitness are unlikely to accumulate in MA experiments employing brother-sister mating (Lynch et al 1999), and selection against these mutations can act either through line extinction or against further accumulation within a line (Schaack et al 2013). We previously demonstrated that lines that went extinct during the experiment were phenotypically distinct from extant lines (McGuigan and Blows 2013).…”

Section: Discussionmentioning

confidence: 94%

Pleiotropic Mutations Are Subject to Strong Stabilizing Selection

et al. 2014

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The assumption that pleiotropic mutations are more deleterious than mutations with more restricted phenotypic effects is an important premise in models of evolution. However, empirical evidence supporting this assumption is limited. Here, we estimated the strength of stabilizing selection on mutations affecting gene expression in male Drosophila serrata. We estimated the mutational variance (V M ) and the standing genetic variance (V G ) from two well-matched panels of inbred lines: a panel of mutation accumulation (MA) lines derived from a single inbred ancestral line and a panel of inbred lines derived from an outbred population. For 855 geneexpression traits, we estimated the strength of stabilizing selection as s = V M /V G . Selection was observed to be relatively strong, with 17% of traits having s . 0.02, a magnitude typically associated with life-history traits. Randomly assigning expression traits to five-trait sets, we used factor analytic mixed modeling in the MA data set to identify covarying traits that shared pleiotropic mutations. By assigning traits to the same trait sets in the outbred line data set, we then estimated s for the combination of traits affected by pleiotropic mutation. For these pleiotropic combinations, the median s was three times greater than s acting on the individual component traits, and 46% of the pleiotropic trait combinations had s . 0.02. Although our analytical approach was biased toward detecting mutations with relatively large effects, likely overestimating the average strength of selection, our results provide widespread support for the prediction that stronger selection can act against mutations with pleiotropic effects.

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Section: Discussionmentioning

confidence: 94%

Pleiotropic Mutations Are Subject to Strong Stabilizing Selection

et al. 2014

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“…Our findings are an exception to the widely held assumption that nearly all mutations are deleterious (Bataillon, 2003; Keightley & Lynch, 2003). There are other reports of high frequencies of beneficial mutations that are either induced or spontaneous (Hall, Mahmoudizad, Hurd, & Joseph, 2008; Perfeito, Fernandes, Mota, & Gordo, 2007; Schaack, Allen, Latta, Morgan, & Lynch, 2013; Zhang, Azad, & Woodruff, 2011). …”

Section: Discussionmentioning

confidence: 99%

Quantifying natural seasonal variation in mutation parameters with mutation accumulation lines

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2018

Ecology and Evolution

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Mutations create novel genetic variants, but their contribution to variation in fitness and other phenotypes may depend on environmental conditions. Furthermore, natural environments may be highly heterogeneous. We assessed phenotypes associated with survival and reproductive success in over 30,000 plants representing 100 mutation accumulation lines of Arabidopsis thaliana across four temporal environments at a single field site. In each of the four assays, environmental variance was substantially larger than mutational variance. For some traits, whether mutational variance was significantly varied between seasons. The founder genotype had mean trait values near the mean of the distribution of the mutation accumulation lines in all field experiments. New mutations also contributed more phenotypic variation than would be predicted, given phenotypic and sequence‐level divergence among natural populations of A. thaliana. The combination of large environmental variance with a mean effect of mutation near zero suggests that mutations could contribute substantially to standing genetic variation.

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Section: Discussionmentioning

confidence: 99%

“…If the Marie population harbors an elevated base mutation load, this may lead to an increased rate of change in the phenotype because new mutations are predicted to accumulate faster in more loaded populations (Agrawal 2002;Shaw and Baer 2011). Given that the Marie lines experienced a greater rate of extinction over the course of the mutation accumulation experiment, an indication of higher mutation load (Lynch 1994), and exhibited large reductions in competitive ability (a complex fitness trait) as a result of mutation accumulation relative to Klamath Lake (Schaack et al 2012), the possibility of high mutation load in this population is plausible.Alternatively, the elevated rate of change in clutch size in Marie may reflect a difference in genotype · environment interactions between the populations. In the current study, all MA lines were assayed in the same benign laboratory environment, but this environment may represent different levels of stress for animals orginating from the Marie vs. Klamath Lake populations (Baer and Lynch 2003).…”

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confidence: 99%

Genomic Background and Generation Time Influence Deleterious Mutation Rates in Daphnia

et al. 2013

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Understanding how genetic variation is generated and how selection shapes mutation rates over evolutionary time requires knowledge of the factors influencing mutation and its effects on quantitative traits. We explore the impact of two factors, genomic background and generation time, on deleterious mutation in Daphnia pulicaria, a cyclically parthenogenic aquatic microcrustacean, using parallel mutation-accumulation experiments. The deleterious mutational properties of life-history characters for individuals from two different populations, and for individuals maintained at two different generation times, were quantified and compared. Mutational properties varied between populations, especially for clutch size, suggesting that genomic background influences mutational properties for some characters. Generation time was found to have a greater effect on mutational properties, with higher per-generation deleterious mutation rates in lines with longer generation times. These results suggest that differences in genetic architecture among populations and species may be explained in part by demographic features that significantly influence generation time and therefore the rate of mutation.A S the ultimate source of all genetic variation, mutation is an important evolutionary force affecting the ability of natural populations to respond to selective pressures. Most spontaneous mutations are deleterious (Lynch et al. 1999;Eyre-Walker and Keightley 2007), which is thought to explain many evolutionary phenomena, including inbreeding depression, mating system evolution, senescence, and risk of extinction to small populations Lynch et al. 1999). Despite the importance of knowing mutation rates in both theoretical and applied biology, few empirical estimates exist other than those for classic genetic model organisms (Baer et al. 2007), and little is known about the factors influencing the rate of mutation among individuals, populations, and species (Lynch 2010).In addition to direct estimates based on sequencing, estimates of the parameters for mutations affecting fitness [i.e., the genome-wide deleterious mutation rate (U) and the average effect (š)] have now been reported for several species (reviewed in Baer et al. 2007). However, little empirical attention has been given to variability in the phenotypic effects of deleterious mutation [i.e., per-generation rates of change in the mean phenotype (DM) and mutational variance (DV)] or to the associated deleterious mutation parameters that can be inferred from these quantities (U andš) among populations within a species. Recent theoretical treatments of mutation-rate evolution, however, predict individual variation in mutation rates (Lynch 2008;Desai and Fisher 2011) and fitness dependence of mutation rates (Agrawal 2002;Shaw and Baer 2011), highlighting the importance of this variability.The deepest understanding comes from recent mutationaccumulation studies in Drosophila melanogaster that provide evidence for variability in mutation rates among genotypes, using bot...

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The effect of spontaneous mutations on competitive ability

Cited by 22 publications

References 45 publications

Pleiotropic Mutations Are Subject to Strong Stabilizing Selection

Pleiotropic Mutations Are Subject to Strong Stabilizing Selection

Quantifying natural seasonal variation in mutation parameters with mutation accumulation lines

Genomic Background and Generation Time Influence Deleterious Mutation Rates in Daphnia

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