Figure 4

Increasing the number of transcription factors increases the complexity and decreases robustness. We trace the steady state attractors of 1000 random networks with 100 nodes and 246 edges each (preserving the node-edge ratio of the E.coli network) where the number of TFs have been varied from 5 to 90 for 100 random initial conditions and report the number of attractors (plot a) and size of the largest attractor (plot b) against the number of transcription factor in the system. As we increase the number of TFs, the number of attractor (and the variance) increases and the size of largest attractor (and the variance) decreases.We also plot knockout (plot c) and initial condition robustness (plot d), in terms of SRR values, of these networks. Both knockout and initial condition robustness are strongly affected by the number of attractors, although the trend is stronger for the initial condition robustness.