Figure 1

Global comparison of all four networks. (a) Topological statistics of all four networks. Because the degrees in the metabolic network are not divided into outward and inward degrees, we treated the metabolic network as an undirected network when calculating the average degree. (b) Association diagram between all four networks. The association between networks is measured by Cramer's V. The thickness of the line between two networks is proportional to the corresponding V. P values are calculated using standard χ² tests.