Experimental Rugged Fitness Landscape in Protein Sequence Space
The stationary value of walker's fitness in the stationary phase, W *, is given on the ordinate. The fitness at the 0th, the mean fitnesses of the 7th and 8′th, of the 12th and 13th, of the 17th and 18th, and of the 19th and 20th generations are indicated with filled circles, triangles, squares, diamonds, and asterisks, respectively. The library size is shown on the abscissa. We regarded the library size at the initial generation as N = 1. The solid curve was drawn with Eqn. (11).