Summary of unified miRNA variants mapping to known miRNAs precursors.

Precursors are annotated known miRNA precursors (pre-miRNAs) in miRBase. Families are annotated known miRNA families in miRBase. miRNA variants are the most abundant sequences mapping to 5′ arm or 3′ arm of known miRNAs precursors. miRNA* are the sequences which can form miRNA::miRNA* duplexes with miRNA variants.