Fitness of the E2 population tested at standard density had decreased by 84 generations. Unlike the other seven populations which either improved or were indistinguishable from the ancestor, the E2 population fitness decreased by half when assayed against the ancestor with both competitors starting at the standard initial density (grey bars). ANC represents the control of the two color variants of the EM ancestor competed against each other (white bar). Data represent the mean and standard error.
Marx BMC Evolutionary Biology 2012 12:109 doi:10.1186/1471-2148-12-109