Figure 7.

Topological meaning of communities detected. (Left) Following [36], kⁱⁿ is the intra-community degree and k^out is the inter-community degree of each node in the metabolic network of E.coli. Summation ( $\sum k^{\mathit{\text{in}}}$ and $\sum k^{\mathit{\text{out}}}$) of intra and inter community degree is over all nodes in each community. The size of the circle is proportional to the size of the community. As is shown, all the communities have $\sum k^{\mathit{\text{in}}}>\sum k^{\mathit{\text{out}}}$ and most nodes are have kⁱⁿ > k^out(Additional file 1: Figure S6). (Right) Inclusion of densely connected subgraphs in the community. The center of each circle corresponds to an observation of a densely connected subgraph K (in any of the 1021 species investigated). X-axis indicates the size of K and Y-axis indicates the maximum overlap of K with a community among all the communities detected from the metabolic network of the same species. The size of the circle is proportional to the number of instances that give the observation.