Figure 2. Characterization of differentially expressed circRNA in OA and NOA samples. (A). The volcano plots display the differential circRNAs expression between the two groups. Red points denote the differentially expressed circRNAs with statistical significance. (fold change ≥1.5 and p <0.05) (B). Heatmap shows the 16 up-regulated circRNAs and 66 down-regulated circRNAs in NOA. (C). The pie charts show the origin of transcription of differentially expressed circRNAs. (D). The chromosomal location of differentially expressed circRNAs is shown in the last figure. Red: up-regulated circRNAs in NOA; green: down-regulated circRNAs in NOA.