Comparison of the miRNA expression profiles determined by quantitative real-time RT-PCR (qPCR) and deep sequencing. a, known miRNAs; b, novel miRNAs and candidate miRNAs. In qPCR, UBQ was used as the internal reference gene, and the relative expression of each miRNA was calculated using a comparative CT (ΔΔCT) method. The miRNA sample with the lowest CT value that corresponds to the highest expression level was selected as the calibrator, in which the expression level was set as 1.0. The relative expression levels of the same miRNA in the other four samples were then normalised by comparing with the highest one in the tested tissues. Three independent biological replicates were performed in this experiment. For each sample, qPCR was performed in triplicate. Each column represents the mean of three samples, and error bars represent the standard deviation. In deep sequencing technology, read counts for each miRNA in one sample were normalised to reads per million of total miRNA reads (RPM). The relative expression of each miRNA was calculated by setting the highest RPM of each miRNA across the five samples as 1.0, and the relative expression of the same miRNA in the other four samples was its RPM divided by the highest RPM.