Genomewide prediction of sno-lncRNAs . (A) Genomewide prediction of sno-lncRNAs with annotated snoRNAs. The numbers of annotated snoRNAs, snoRNAs in introns or snoRNAs forming pairs in any single intron were compared across human (blue), rhesus (green) and mouse (yellow). Rhesus snoRNAs were transposed from human and mouse annotations. Note that only a few of snoRNAs could form pairs in any single intron, and even fewer sno-lncRNAs (highlighted by asterisk) could be detected with poly(A)-/ribo- RNA-seq signals. (B) Genomewide prediction of sno-lncRNAs with an intron-annotation-independent algorithm. For each two adjacent snoRNAs (blue bars) within 10 kb, RPKM of snoRNAs (blue regions) and internal region (pink regions) in poly(A)-/ribo- RNA-seq datasets were evaluated with a set of criteria to identify novel sno-lncRNAs (Methods). In total, 19 sno-lncRNAs were identified in examined species and cell lines (Table 1).