Transcript of unknown function

Transcripts of unknown function (TUFs) is the name that has been suggested for known RNA transcripts of DNA whose function is unclear. Most TUFs are probably ncRNAs, such as snRNAs or snoRNAs, but could also represent a whole new class of ncRNA. The DNA sequences for TUFs reside in the intergenic or intronic regions of the genome, which is often called junk DNA. This currently makes up much of the human genome, although the percentage of the genome that falls under the TUFs category is likely to go down significantly as more progress is made towards understanding the many roles of RNA.