The changes in Z scores for the antimotifs under assumption of perturbed regulator modes. The changes in the Z scores are shown in plots with closed triangles along the proportions with which the TF modes of the connections were randomly swapped between positive and negative. This perturbation procedure was repeated ten times with each proportion of 1%, 5%, 10%, 15% and 20% for (a) antimotif N-N targeting effecters, i.e. effecter-targeting FFCs composed of an originating repressor regulator with autoregulation and an intermediary repressor regulator without autoregulation, and (b) antimotif N-P targeting effectors, i.e. effecter-targeting FFCs composed of an originating repressor regulator with autoregulation and an intermediary activator regulator without autoregulation. The plots show that the confidence levels represented by the Z scores increase despite the mode perturbation procedure. This seemingly paradoxical phenomenon is attributable to the fact that, even if the mode is perturbed, both the antimotif N-N and antimotif N-P targeting effectors come to fall into the category of the originating-only autoregulated FFCs targeting effecters. Therefore, the mode perturbation procedures move the confidence levels for these FFCs closer to the confidence level of the category of the originating-only autoregulated FFCs targeting effecters, the Z score of which is -1.911 (see Figure 1b). The closed circle on each y-axis represents the Z score of the main results (i.e. without perturbation).