Differences between miRNAs and siRNAs. a, A scheme of miRNA and siRNA precursors and
duplexes. While miRNAs are usually produced from short hairpins carrying
mismatches in their stem region, siRNAs are produced from long hairpins with
stems of perfect complementarity. miRNA precursors usually give rise to a single
duplex whereas siRNA precursors are a source for multiple duplexes.
b, Small RNA profiles along a pre-miRNA sequence, here
exemplified by miR-2024a of Nematostella vectensis. Note the
homogenous product with the dominant guide strand (mature miRNA) and the
neglectable passenger strand (miRNA*). c, Small RNA profiles along
an siRNA precursor sequence, here exemplified by miR-2024c of N.
vectensis. This siRNA locus was originally annotated as miRNA, but
later determined to be an siRNA due to the fact it gives rise to multiple small
RNAs 45. The x-axis in b) and
c) indicates the position along the hairpin sequence with paired (brackets) and
unpaired nucleotides (dots). ppm = parts per million. (b and c) modified from
45, with
permission.