Numt

Numt is an abbreviated term for “nuclear mitochondrial DNA”, which describes any transfer or “transposition” of cytoplasmic mitochondrial DNA sequences into the separate nuclear genome of a eukaryotic organism. As whole genome sequencing projects accumulate, more and more Numts have been detected in many diverse eukaryotic organisms (see http://www.pseudogene.net for one list of examples).

The first use of the term was made to describe a transposition of approximately 7.9 kilobase pairs of the cytoplasmic mtDNA genome into the nucleus of the domestic cat (Felis silvestris catus), where Numt is tandemly repeated, 38-76 times at a single genomic locus on cat chromosome D2.[1] Many Numts are transcriptionally inactive similar to some satellite (or junk) DNA, though they may be considered as part of the Serial Endosymbiosis Theory (SET) or endosymbiotic theory for the origin of eukaryotic cells and organelles.

The most recent reports describe 755 NUMTs of variable length (from 38 to 14835 base pairs) in the human genome.[2] NUMTs in mammalian genomes have been shown to be non-random and to be associated with retrotransposons [3] as well as mitochondrial origin tRNA-lookalikes.[4]

Notes

  1. Lopez, J.V., Yuhki, N., Modi, W., Masuda, R., O'Brien, S.J.; Yuhki; Masuda; Modi; O'Brien (1994). "Numt, a recent transfer and tandem amplification of mitochondrial DNA in the nuclear genome of the domestic cat". Journal of Molecular Evolution 39 (2): 174–190. doi:10.1007/BF00163806 (inactive 2015-02-01). PMID 7932781.
  2. Ramos A. et al. (2011). "Nuclear Insertions of Mitochondrial Origin: Database Updating and Usefulness in Cancer Studies". Mitochondrion 11 (6): 946–53. doi:10.1016/j.mito.2011.08.009. PMID 21907832.
  3. Tsuji J. et al. (2012). "Mammalian NUMT insertion is non-random". Nucleic Acids Res 40 (18): 9073–88. doi:10.1093/nar/gks424. PMID 22761406.
  4. Telonis Aristeidis G. et al. (2014). "Nuclear and Mitochondrial tRNA-lookalikes in the Human Genome". Frontiers in Genetics 5: 00344. doi:10.3389/fgene.2014.00344. PMC 4189335. PMID 25339973.

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