Figure 2: Distribution of the secondary structure conservation scores between human Secondary structure conservation (str_sim) was calculated for the pairs of predicted secondary structures from the pre-miRNA sequences of human and nine other species. Panels (A) to (I) indicate the distributions of str_sim values from the same species pairs shown in the legend of Figure 1. N stands for the number of premiRNA homologues over str_sim values between human and each of other species. Closed bars indicate the distributions of str_sim values from the sequence pairs of known miRNAs registered in miRBase. Open bars show the distributions of str_sim values from those of human known miRNAs and homologues found in the genomes of other species. No known miRNA sequence data were available for gibbon and marmoset. The thresholds to define outliers were calculated based on the str_sim distributions from known miRNA gene pairs at a significance level of p<0.01, and they are also shown in the panels.