Filtering interaction datasets to improve their accuracy. (a) The percentages of interactions sharing GO terms at various depths in the GO hierarchy are compared for interactions predicted by the high-confidence interactions from each model organism (core yeast, core worm and core fly), as well as for the complete datasets from each organism (all yeast, all worm, all fly). For comparison, the percentage of shared GO terms is shown for a randomly generated network of the same size as the complete human network (random pairs). The x-axis indicates the depth in the GO hierarchy being considered, and the y-value the percentage of interaction partners (with known GO annotations) that share GO annotations at this depth or deeper. (b) The percentages of interactions sharing GO terms at different levels in the GO hierarchy are compared for interactions predicted by core interactions in two or more species (two species (core)), by interactions in the complete datasets of two or more species (two species), for interactions predicted by more than one experimental method in yeast (two methods), by any core interaction (all core), by any interaction (all), or by a randomly generated interaction network of the same size as the complete human interaction network (random pairs). All values shown are the percentage of non-self interactions between pairs of proteins that both have at least one associated GO term at the indicated depth in the GO hierarchy.