Data from: Negative epistasis between beneficial mutations in an evolving bacterial population

Epistatic interactions between mutations play a prominent role in evolutionary theories. Many studies have found that epistasis is widespread, but they have rarely considered beneficial mutations. We analyzed the effects of epistasis on fitness for the first five mutations to fix in an experimental population of Escherichia coli. Epistasis depended on the effects of the combined mutations—the larger the expected benefit, the more negative the epistatic effect. Epistasis thus tended to produce diminishing returns with genotype fitness, although interactions involving one particular mutation had the opposite effect. These data support models in which negative epistasis contributes to declining rates of adaptation over time. Sign epistasis was rare in this genome-wide study, in contrast to its prevalence in an earlier study of mutations in a single gene.Khan_etal_analysisR script used to: estimate beneficial mutation effects and epistasis parameters, perform statistical tests and generate all figures presented in Khan et al. (2011), except figures 1 and 4. Takes as input the file: genotype_fitness.txt.Khan_etal_Fig1R script to generate figure 1 of Khan et al. (2011). Takes as input the file: genotype_fitness.txt.Khan_etal_Fig4R script to generate figure 4 of Khan et al. (2011). Takes as input the file: genotype_fitness.txt.genotype_fitnessText file containing all replicate fitness measurements of each constructed genotype. Includes columns: strain, strain number; genotype, beneficial mutations present where r = rbs, t = topA, s = spoT, g = glmUS and p = pykF; mutations, number of beneficial mutations in the genotype; w, fitness estimate; block, experimental block; Plate, physical container used for the competition. This file is the input file for all analyses presented in Khan et al. (2011) Negative epistasis between beneficial mutations in an evolving bacterial population.raw_competition_dataText file containing raw data from all competition experiments. All competitions were performed over 2 transfer cycles. Fitness values from this file are summarized in 'genotype_fitness.txt', which is the input file for all analyses presented in Khan et al. (2011) Negative epistasis between beneficial mutations in an evolving bacterial population