Data from: Diminishing-returns epistasis decreases adaptability along an evolutionary trajectory

Populations evolving in constant environments exhibit declining adaptability. Understanding the basis of this pattern could reveal underlying processes determining the repeatability of evolutionary outcomes. In principle, declining adaptability can be due to a decrease in the effect size of beneficial mutations, a decrease in the rate at which they occur, or some combination of both. By evolving Escherichia coli populations started from different steps along a single evolutionary trajectory, we show that declining adaptability is best explained by a decrease in the size of available beneficial mutations. This pattern reflected the dominant influence of negative genetic interactions that caused new beneficial mutations to confer smaller benefits in fitter genotypes. Genome sequencing revealed that starting genotypes that were more similar to one another did not exhibit greater similarity in terms of new beneficial mutations, supporting the view that epistasis acts globally, having a greater influence on the effect than on the identity of available mutations along an adaptive trajectory. Our findings provide support for a general mechanism that leads to predictable phenotypic evolutionary trajectories.mutation_dataSummary of mutates genes identified in evolved clones isolated from replay populationsfig3R script to generate figure 3fig3_anc-evInput data required to generate figure 3fig1.b R scriptR script to generate figure 1bfitness change_vs_initial fitnes.Rfig1.b input dataInput data necessary to generate figure 1bfitnesschange.tabfig4_replay_clone_mutationsInput to fig4 R script. Summary of mutated genes in clones isolated from replay populations.Fig4_replay_clone_mutations.txtfig4_mutations_in_founder_also_in_replayInput file for fig. 4 R script. Summarizes mutations present in founders that also occurred in some replay clones. These mutations are omitted from calculation of the convergence metric.Fig4_mutations_progenitor_also_in_replay.txtfig4_PI_CI matrixR script to generate figure 4.Fig4_PI_CI matrix.RFunding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: DEB-125365