Data from: A comparison of methods to measure fitness in Escherichia coli

In order to characterize the dynamics of adaptation, it is important to be able to quantify how a population's mean fitness changes over time. Such measurements are especially important in experimental studies of evolution using microbes. The Long-Term Evolution Experiment (LTEE) with Escherichia coli provides one such system in which mean fitness has been measured by competing derived and ancestral populations. The traditional method used to measure fitness in the LTEE and many similar experiments, though, is subject to a potential limitation. As the relative fitness of the two competitors diverges, the measurement error increases because the less-fit population becomes increasingly small and cannot be enumerated as precisely. Here, we present and employ two alternatives to the traditional method. One is based on reducing the fitness differential between the competitors by using a common reference competitor from an intermediate generation that has intermediate fitness; the other alternative increases the initial population size of the less-fit, ancestral competitor. We performed a total of 480 competitions to compare the statistical properties of estimates obtained using these alternative methods with those obtained using the traditional method for samples taken over 50,000 generations from one of the LTEE populations. On balance, neither alternative method yielded measurements that were more precise than the traditional method.Methods.3.FormsThis file contains all the raw data for this manuscriptMethods.MeansThis file has the precalculated means for each method at each time point. All of this can be calculated from the raw data file, but this makes things more convenient.Methods Executed ScriptThis is the analysis script for this manuscript. Please note that it is saved as a .txt file, though it is designed for use in R. Anyone wishing to repeat the analysis will need to either copy and paste this into an R window, or else save the file as an appropriate R script extension