An overview of pre-rmiRNAs with high similarity to canonical pre-miRNAs. (a) Sequence comparison between detected precursor-rmiRNAs (pre-rmiRNAs) and their canonical pre-miRNAs. Mature (guide) miRNA strand is colored with red and passenger is colored with blue. Differences in base sequences between pre-rmiRNAs and pre-miRNAs are highlighted in yellow and box lines. (b) Comparison of secondary structure of pre-rmiRNAs with that of their canonical pre-miRNAs. These rmiRNAs contain the identical sequences to canonical ones in both guide and passenger. This group contains only a few polymorphisms in loop and terminal region.