Target site conservation excess of annotated and putative miRNA. The proportion of seed families with target site conservation excess (p < 0.05) among annotated conserved miRNA (Am/green), putative conserved miRNA excluding ncRNA-derived miRNA (Pm/red), and ncRNA-derived putative conserved miRNA identified in human dataset (A) and overlapping between human and rhesus datasets (B). The background proportion (Bg/grey) was calculated by 1,000 random simulations of seed region sequences (see Methods for details). The error bars show 95% confidence interval of the simulations. The stars above the bars (**) indicate significance level based on the simulation results.