Analysis of signed biological networks in the perspective of structural balance theory

Analysis of signed biological networks has been an interest of some researchers in recent years. We consider communities and balanced clusters as two structural patterns that may reveal different structures in the networks. Although biological networks tend to structural balance، this study clarifies adhesive communities in some transcriptional networks of ecoli and yeast differ from the balanced clusters and have significantly more negative links in their structure. This difference may be used as an index in categorizing various systems'' structure and function. Also we study the important role of the positive links between balanced clusters، even though the links between these clusters are mostly negative. Analyzing data of some Gene Regulatory Networks، shows that perturbing the genes located at these links، has a larger effect on the system and causes more distance from the initial equilibrium state. So، signed clustering and detecting the links between these clusters can be considered as an effective approach in detecting the functional units and the key components in the system. This can be useful in applications like gene targeting in drug synthesis.