The rat circRNA repertoire. (A) Comparison of the number of circRNA species across the 11 rat tissues. (B) Fractions of exonic, intronic, and intergenic circRNA species within the repertoire. (C) Histogram of the number of exons in the exonic circRNAs of rats. (D) Histogram of circRNA length in rats. (E) Cumulative distribution of the PhastCons scores of both linear and circular transcripts at the three codon positions. A significantly increased PhastCons score was observed for the circular transcripts compared with the linear transcripts. The P-values were calculated with the Kolmogorov–Smirnov test. (F) Fractions of mammalian-common, rodent-specific, and rat-specific circRNA species within the repertoire. (G) Comparisons of exon numbers among the mammalian-common, rodent-specific, and rat-specific circRNAs.