We mapped the sequence reads back to human pre-miRNA, quantifying the expression levels of pre-miRNAs, mature miRNA and isomiRs.
a: The human pre-miRNA and mature miRNA are based on the definition of miRBase 16. Totally, there are 1,048 pre-miRNAs and 1,223 mature miRNAs, resulting in 1,366 miRNA/pre-miRNA pairs.
b: According to miRBase 16, 730 out of 1,048 human pre-miRNAs encode only one mature miRNA at one arm, either 5p or 3p arm. With the improvement on NGS's sequencing intensity, we detected additional opposite-arm mature miRNAs at the pre-miRNAs originally encoding only one miRNA.