Figure 3 shows that the distribution of scores between gene pairs has an approximately power law distribution, with many scores near the minimum of 0.001, and a few high scores of up to 300. Pairs of genes which are in the same KEGG pathway [6] tend to have a stronger link than others, with median and mean scores of 0.5 and 2.5, while for all genes the corresponding values of 0.2 and 0.5 respectively. When only those pairs of genes involved in physical interactions included in the BIND database [64] are considered, the median and mean are dramatically higher, at 3.2 and 9.0 respectively. Note that it is not our aim to reproduce either of these known gene-gene relationships, but to introduce a more general, literature based measure.
