Statistics and fiber coverage of the two GRNs.

For E. coli we start with the 879 operon-GRN from Step 0.2 (see previous Table 1). For E. coli, Step 1 collapses the 416 nodes within fibers into 92 fiber-collapsed nodes (one for each fiber), to give the collapsed-fibers 555 nodes Base-GRN. For B. subtilis, the 2263 fibered nodes are collapsed into 302 fiber-collapsed nodes (one for each fiber), resulting in the 521 nodes Base-GRN. Step 2 removes all the nodes in the outer shell, including 82 of the fiber-collapsed nodes for E. coli and 290 for B. subtilis, thus leaving only the minimal GRN. The minimal networks are composed of the nodes in SCC and the connectors nodes. The k-shells are actually much bigger, but we count the genes inside them after collapsing the fibers, resulting in only 82 fiber-collapsed nodes (in the case of E. coli) instead of counting all the original nodes that belong in these fibers.