Fig 4. Growth Selection Parameters.

The parameters of growth-based selections should be chosen such that the range of enrichment ratios for the population lies between-4 and 4. A. Enrichment ratios as a function of the individual growth rate compared to the population growth rate. Following one generation of population growth (blue) the enrichment ratios remain around zero. Increasing the number of population generations the experiment is allowed to grow (1 generation, blue, 5 generations, red and 10 generations, green) increases the experimental resolution in discriminating mutant growth phenotypes. B. Enrichment ratios as a function of average population generation (g_p) for various $\frac{{\mu }_i}{{\mu }_p}$. For $\frac{{\mu }_i}{{\mu }_p}$ values less than one (0.1, red; 0.5, blue; and 0.667, green) the enrichment ratios decrease with increasing population generations. Variants with values $\frac{{\mu }_i}{{\mu }_p}$ values above one (1.5, black) show enhanced enrichment with increasing population generations.