Fig. 9. Connections between pathway redundancy and synthetic lethal interactions. Consider a hypothetical cellular network module (a) that receives exogeneous signals through node A and whose sink node F determines the response to the signal (or the phenotype). There are two node-independent (redundant) pathways between nodes A and F that can compensate for each other in case of node disruptions. By defining synthetic lethal interactions as pairs of nodes whose loss causes the disconnection of nodes A and F, one would find graph b. The two graphs present complementary and non-overlapping information.