Similarity of linked and unlinked nodes. Jaccard similarity coefficients between linked and unlinked nodes in the therapeutic network. LDG – linked disease-gene, UDG – unlinked disease-gene, LDC – linked disease-chemical, UDC – unlinked disease-chemical, LCG – linked chemical-gene, UCG – unlinked chemical-gene. In all three sets, the linked nodes were more similar than unlinked nodes determined by Mann Whitney U tests (p < 0.01). The median for all unlinked node pairs is 0, with the medians for the linked pairs: DG – 0.026, DC – 0, CG – 0.032.