Known Positive Set and Algorithm Prediction Overlap. Venn diagrams showing, for five representative species-pair combinations, the overlap between known positive sets (grey circle) and Bio::Homology::InterologWalk predicted set (white circle). In all observed cases, the algorithm completely rescues the known positive samples and, in addition, proposes new potential interactions and interaction candidates. The new predictions account for a minimum of 53% to a maximum of 90% of the total IDs produced and a minimum of 73% to a maximum of 96% of the total PPIs. The results suggest that even in the case of well studied organisms - provided that the hypothesis of functional conservation between orthologues is correct - most physical protein associations are still unknown.