'''Transcripts of unknown function (TUFs)''' is the name that has been suggested for known [[RNA|RNA transcripts]] of [[DNA]] whose function is unclear. Most TUFs are probably [[Non-coding RNA|ncRNAs]], such as [[RNAi]] or [[snoRNA|snoRNAs]]s, but could also represent a whole new class of ncRNA.<ref name=Gingeras>{{cite journal | last = Gingeras | first = Thomas R. | year = 2007 | title = Origin of phenotypes: Genes and transcripts | journal = Genome Research | volume = 17| issue = 6 | pages = 682–690 | doi = 10.1101/gr.6525007 | pmid = 17567989 }}</ref> The DNA sequences for TUFs reside in the [[Intergenic region|intergenic]] or [[Intron|intronicintron]]ic 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.
