Distributions of gene distance of adjacent genes. (a) The gene distance is measured as the number of base pairs in between the coding regions of two genes. (b) The gene distance is measured as the number of base pairs in between the transcription start sites (TSSs) of two h2h genes. H2h with high association represents gene pairs with functional similarity higher than the genome average; while h2h with low association represents the remaining h2h gene pairs (see the Methods section for the details).
Chang et al. BMC Genomics 2012 13(Suppl 1):S11 doi:10.1186/1471-2164-13-S1-S11