Fig. 2
Expression levels of the 24 candidate circRNAs in a wide range of human tissues. The average expression levels of the single candidate circRNA described by Liu et al. and the 23 candidate circRNAs described by Jiang et al. in 31 distinct normal human tissues as quantified by bulk RNA sequencing, compared to those of 500 background circRNAs selected at random. Expression levels represent counts of backsplice junction spanning reads normalized per million, and are visually presented unity scaled between 0 and 1 to facilitate comparison. For each individual circRNA, the tissue of maximum expression is indicated, along with the degree of brain enrichment in terms of the fold difference observed between brain and non-brain tissues. Furthermore, the proportion of circRNAs within each set of circRNAs that respectively exhibit maximal expression in either brain tissue or blood are also indicated, along with the median brain enrichment. aThe proportions of brain expressed and blood expressed circRNAs amongst the candidates were statistically compared to background using Fisher’s exact test. Median brain enrichment amongst the candidates were statistically compared to background using either bone-sample or ctwo-sample Mann–Whitney U test. *Statistically significant compared to background.
