Fig. 4

Characterization of different subclasses of circRNAs. a CircRNAs identified in the six vertebrates by CIRI2 and other tools. The first five columns show the numbers of identified circRNAs, full-length circRNAs, cirexons, IRES, and ORFs, respectively. The remaining columns indicate the number of circRNAs from the different subclasses. b–e The relative expression value (b), the tissue specificity index (c), the junction ratio across tissues (d), and the length distribution (e) of different types of circRNAs. Significance has been calculated between exonic and other types of circRNAs using the Wilcoxon test (**P < 0.01). f The Venn plot shows the number of shared genes and circRNAs across vertebrates. g The proportion of circRNA subclasses (except exonic ones) in different ancestral nodes (denoted by a, b, c, and d). h The proportion of circRNAs expressed in specific tissues across the different ancestral nodes