The calculated phase-shift statistics distribution (totally 55 pairwise candidates for the APGs group in the multi-feedback p53 pathway). The blue bold curve represents the integral tendency of gene pairs with leading phase shifts (positive), the red for the pairs with lagging phase shifts (negative), and the green for those without detected phase shift (undirected), i.e. there might be no regulatory activities between corresponding gene pairs.
Tang et al. BMC Systems Biology 2010 4(Suppl 2):S3 doi:10.1186/1752-0509-4-S2-S3