miRNAs represent a minority of the total sncRNA repertoire.A, quantity of different sncRNAs present across various mouse tissues and cells. Data are derived from Ref. (12). B, sequence diversity of different sncRNAs in the mouse, including the cumulative sum of mouse miRNA types sourced from miRbase. The types of other detected sncRNAs are compiled from pooled data of tissues and cells provided in Ref. (12). The sncRNAs depicted in the inner circle represent detected sncRNAs that appear in at least two independent sequencing libraries. The outer circles represent the theoretical possibilities for sncRNA generation, based on potential cleavage at any position of the RNAs (i.e., Y RNAs, vtRNAs, tRNAs, rRNAs, snRNAs, and snoRNAs) to produce sncRNA products of 15 to 44 nucleotides in length. sncRNA, small noncoding RNA; snoRNA, small nucleolar RNA; snRNA, small nuclear RNA; vtRNA, vault RNA.