Use this filter to identify ncRNAs that overlap known snoRNAs or miRNAs. miRNA and snoRNA mappings were obtained from mirBase (Griffiths-Jones et al (2008) <i>Nucleic Acids Res</i> 36:D154-58) and UCSC Genome Browser (Karolchik et al (2008) <i>Nucleic Acids Res</i> 36: D773-9) , respectively.