definiens: shall mean a structurally defined functional RNA molecule usually between 19 and 25 nucleotides inlength, which is derived from an endogenous, genetically - encoded non - coding RNA which is predicted to be processed into ahairpin RNA structure that is a substrate for the double - stranded RNA - specific ribonuclease Drosha and subsequently ispredicted to serve as a substrate for the enzyme Dicer, a member of the RNase III enzyme family ; including, withoutlimitation, those miRNAs exemplified in miRBase ( http://microrna.sanger.ac.uk/ ) . shall mean a single - stranded or double - stranded oligonucleotide with the same or substantiallysimilar - base composition and sequence ( including chemically modified bases ) as a particular natural, miRNA and which isdesigned to mimic the activity of such miRNA . For clarity, miRNA Mimic excludes a double - stranded oligonucleotide whichfunctions or is designed to function as an siRNA