shRNA is short hairpin RNA, double stranded RNA (dsRNA) which is created in the cell from a DNA construct encoding a sequence of single stranded RNA and its complement, separated by a stuffer fragment, allowing the RNA molecule to fold back on itself, creating a dsRNA molecule with a hairpin loop. (What is ddRNAi). In its synthetic form, shRNA suffers from the same constraints as outlined above for siRNA. However, when it is produced inside the cell from a DNA construct, it has the positive characteristics of siRNA, yet is produced continuously by the target cell’s own machinery.