The file consists of data showing the fitness (expected and observed) relative to the wild type and epistasis of different auxotrophic genotypes in minimal media with either fructose or succinate as the carbon source. The file also contains data of control experiments showing fitness relative to the wild type of genotypes subject to successive rounds of transduction with the same phage genotype and also the fitness (Malthusian parameter) of auxotrophic genotypes with and without the kanamycin resitance cassette.