Fig. 2

Illustration of how to select the globally independent gens. A is the independent gene of B and D; B is the independent gene of C, B is also the dependent gene of E; F is a single node gene; H, I and G are in a feedback sub-network. In category 1, we identified A, E and F with indegree = 0 as the globally independent genes (marked in red). In category 2, H, I and G are all identified as the globally independent genes (marked in red). The nodes in green indicate genes that are both dependent genes and independent genes of some other genes. The blank nodes indicate genes are only dependent genes of some other genes