Mammalian-wide interspersed repeat

Mammalian-wide interspersed repeats (MIRs) are transposable elements in the genomes of some organisms and belong to the group of Short interspersed nuclear elements (SINEs).

Incidence

MIRs are found in all mammals (including marsupials).[1]

In human

It is estimated that there are around 368,000 MIRs in the human genome.[2]

Structure

The MIR consensus sequence is 260 basepairs long and has an A/T-rich 3' end.[1]

Propagation

Like other Short interspersed nuclear elements (SINEs), MIR elements used the machinery of LINE elements for their propagation in the genome, which took place around 130 million years ago. They cannot retrotranspose anymore since the loss of activity of the required reverse transcriptase.[3]

History of Discovery

MIR elements have been first described in 1989[4] and were first referred to as "Mammalian interspersed repeats" in 1992.[5]

References

  1. 1 2 Smit, Arian F. A.; Riggs, Arthur D. (1995). "MIRs are classic, tRNA-derived SINEs that amplified before the mammalian radiation". Nucleic Acids Research. 23 (1): 98–102. doi:10.1093/nar/23.1.98.
  2. ↑ Lander; et al. (2001). "Initial sequencing and analysis of the human genome.". Nature. 409 (6822): 860–921. doi:10.1038/35057062. PMID 11237011.
  3. ↑ Krull, M; Petrusma, M; Makalowski, W; Brosius, J; Schmitz, J (August 2007). "Functional persistence of exonized mammalian-wide interspersed repeat elements (MIRs).". Genome Research. 17 (8): 1139–45. doi:10.1101/gr.6320607. PMC 1933517Freely accessible. PMID 17623809.
  4. ↑ Donehower, Lawrence A.; Slagle, Betty L.; Wilde, Margaret; Darlington, Gretchen; Butel, Janet S. (1989). "Identification of a conserved sequence in the non-coding regions of many human genes". Nucleic Acids Research. 17 (2): 699–722. doi:10.1093/nar/17.2.699.
  5. ↑ Jurka, Jerzy; Walichiewicz, Jolanta; Milosavljevic, Aleksandar (October 1992). "Prototypic sequences for human repetitive DNA". Journal of Molecular Evolution. 35 (4): 286–291. doi:10.1007/BF00161166.
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