Robustness vs. modularity.

Panels A and B show data for the robustness against metabolic perturbations. A displays robustness of the system as a whole; B shows the robustness measured over the perturbed metabolites only. Panels C and D show the corresponding plots for robustness against genetic perturbations. Circles represent perturbations made in one module; crosses indicate data for perturbations made in different modules. The data is averaged over more than 500 runs (network realizations). The errorbars in the average are smaller than the symbol size.