Evaluation of functional homogeneity and semantic similarity densities across different thresholds. Average (A) information content and (B) all pair-wise semantic similarity values are plotted with increasing numbers of rank normalized GO terms n (see Fig. 3) for "breast/up-regulated miRNA cluster" from Volinia et al.  (index 1 in Supplementary Table S1 in 'Additional file 1') by applying target variation #6 in Table 1, GO BP category. Measures containing miRNA-centric μ (in blue) like (ρ, μ) (in pink) and (τ, μ) (in sky blue) consistently outperform traditional gene-centric ρ (in red) measures at all levels.