Effects of population density and population size on starvation-induced diversification.

<p>93U204 cells were starved in 10 mL phosphate-buffered saline at densities of 10⁹, 10⁷, 10⁵, and 10³ CFU/mL (A), or in 100, 10 and 3 mL at a density of 10⁹ CFU/mL (B). The Shannon diversity index (top), percentage of cells with the wild-type (WT) phenotype (middle), and survival rate (bottom) of each population on days 14 (white bar), 28 (light grey bar), and 42 (dark grey bar) are shown. At day 14, phenotypic diversity (indicated by Shannon index) correlated positively with cell density, and percentage of WT and ratio of final to initial populations correlated negatively with cell density. After day 14, the trends in Shannon index and WT cell percentage were less apparent. Increased population size did not lead to more beneficial mutations in the population.