Number of essential reactions predicted by genome-scale metabolic models and essential genes in genome-scale experimental assays for different metabolic subsystems.

Each reaction and gene were counted only once, even if present (or present and essential) in more than one model or experimental dataset. Single, double and triple asterisks indicate p-values less than 0.05, 0.01 and 0.0001, respectively, after a Fisher's exact test for count data testing independence of the number of essential vs the number of non-essential mapped genes and reactions.