{{short description|Known RNA transcripts of DNA whose function is unclear}}
{{Orphan|date=February 2009}}
'''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]]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 sequencessequence]]s for TUFs reside in the [[Intergenic region|intergenic]] or [[intron]]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.
== Categories of TUFs ==
Broadly speaking, TUFs can be classified into three categories:<ref name=Gingeras/>
<br />1. # TUFs that are complementary to [[Sense (molecular biology)|sense transcripts]] of [[gene|protein-coding genes[[gene]]s
<br />2. # TUFs that are novel [[Protein isoform|isoform]] transcripts of protein-coding genes; this can include expressed [[pseudogene|expressed pseudogenes]]s
<br />3. # TUFs that reside on the same strand as protein-coding genes in the intronic region or entirely in the intergenic region
== Other information ==
There are very few details known about TUFs, which is why the phrase even exists, but one thing that has been shown several times is that they are not very conserved between [[mice]] and humans. This could be due to a number of factors, including more recent [[evolution]] in the [[primate]] lineage or extensive [[post-transcriptional modification]] of the RNA.<ref name=Gingeras/>
