Indel

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Indel is a molecular biology term for an insertion or deletion of bases in the genome of an organism. It is classified among small genetic variations, measuring from 1 to 10 000 base pairs in length,[1][2][3][4][5][6][7] including insertion and deletion events that may be separated by many years, and may not be related to each other in any way.[8] A microindel is defined as an indel that results in a net change of 1 to 50 nucleotides.[9]

In coding regions of the genome, unless the length of an indel is a multiple of 3, it will produce a frameshift mutation. For example, a common microindel which results in a frameshift causes Bloom syndrome in the Jewish or Japanese population.[10] Indels can be contrasted with a point mutation. An indel inserts and deletes nucleotides from a sequence, while a point mutation is a form of substitution that replaces one of the nucleotides without changing the overall number in the DNA. Indels can also be contrasted with Tandem Base Mutations (TBM), which may result from fundamentally different mechanisms.[11] A TBM is defined as a substitution at adjacent nucleotides (primarily substitutions at two adjacent nucleotides, but substitutions at three adjacent nucleotides have been observed).[12]

Indels, being either insertions, or deletions, can be used as genetic markers in natural populations, especially in phylogenetic studies.[13][14] It has been shown that genomic regions with multiple indels can also be used for species-identification procedures.[15][16][17]

An indel change of a single base pair in the coding part of an mRNA results in a frameshift during mRNA translation that could lead to an inappropriate (premature) stop codon in a different frame. Indels that are not multiples of 3 are particularly uncommon in coding regions but relatively common in non-coding regions.[18][19] There are approximately 192-280 frameshifting indels in each person.[20] Indels are likely to represent between 16% and 25% of all sequence polymorphisms in humans.[1] In fact, in most known genomes, including humans, indel frequency tends to be markedly lower than that of single nucleotide polymorphisms (SNP), except near highly repetitive regions, including homopolymers and microsatellites.[citation needed]

The term "indel" has been co-opted in recent years by genome scientists for use in the sense described above. This is a change from its original use and meaning, which arose from systematics. In systematics, researchers could find differences between sequences, such as from two different species. But it was impossible to infer if one species lost the sequence or the other species gained it. For example, species A has a run of 4 G nucleotides at a locus and species B has 5 G's at the same locus. If the mode of selection is unknown, one can not tell if species A lost one G (a "deletion" event") or species B gained one G (an "insertion" event). When one cannot infer the phylogenetic direction of the sequence change, the sequence change event is referred to as an "indel".[citation needed]

See also[edit]

References[edit]

  1. ^ a b Mills RE, Luttig CT, Larkins CE, Beauchamp A, Tsui C, Pittard WS, Devine SE (September 2006). "An initial map of insertion and deletion (INDEL) variation in the human genome". Genome Research. 16 (9): 1182–1190. doi:10.1101/gr.4565806. PMC 1557762. PMID 16902084.
  2. ^ Mullaney JM, Mills RE, Pittard WS, Devine SE (October 2010). "Small insertions and deletions (INDELs) in human genomes". Human Molecular Genetics. 19 (R2): R131–R136. doi:10.1093/hmg/ddq400. PMC 2953750. PMID 20858594.
  3. ^ Kondrashov AS, Rogozin IB (February 2004). "Context of deletions and insertions in human coding sequences". Human Mutation. 23 (2): 177–185. doi:10.1002/humu.10312. PMID 14722921. S2CID 24181754.
  4. ^ Ogurtsov AY, Sunyaev S, Kondrashov AS (August 2004). "Indel-based evolutionary distance and mouse-human divergence". Genome Research. 14 (8): 1610–1616. doi:10.1101/gr.2450504. PMC 509270. PMID 15289479.
  5. ^ William M. Gelbart; Lewontin, Richard C.; Griffiths, Anthony J. F.; Miller, Jeffrey H. (2002). Modern genetic analysis: integrating genes and genomes. New York: W.H. Freeman and CO. pp. 736. ISBN 0-7167-4382-5.
  6. ^ Gregory TR (January 2004). "Insertion-deletion biases and the evolution of genome size". Gene. 324: 15–34. doi:10.1016/j.gene.2003.09.030. PMID 14693368.
  7. ^ Halangoda A, Still JG, Hill KA, Sommer SS (2001). "Spontaneous microdeletions and microinsertions in a transgenic mouse mutation detection system: analysis of age, tissue, and sequence specificity". Environmental and Molecular Mutagenesis. 37 (4): 311–323. doi:10.1002/em.1038. PMID 11424181. S2CID 10441407.
  8. ^ Mank R, Wilson MD, Rubio JM, Post RJ (March 2004). "A molecular marker for the identification of Simulium squamosum (Diptera: Simuliidae)". Annals of Tropical Medicine and Parasitology. 98 (2): 197–208. doi:10.1179/000349804225003118. PMID 15035730. S2CID 6002104.
  9. ^ Gonzalez KD, Hill KA, Li K, Li W, Scaringe WA, Wang JC, et al. (January 2007). "Somatic microindels: analysis in mouse soma and comparison with the human germline". Human Mutation. 28 (1): 69–80. doi:10.1002/humu.20416. PMID 16977595. S2CID 12629541.
  10. ^ Kaneko T, Tahara S, Matsuo M (May 1996). "Non-linear accumulation of 8-hydroxy-2'-deoxyguanosine, a marker of oxidized DNA damage, during aging". Mutation Research. 316 (5–6): 277–285. doi:10.1016/S0921-8734(96)90010-7. PMID 8649461.
  11. ^ Hill KA, Wang J, Farwell KD, Sommer SS (January 2003). "Spontaneous tandem-base mutations (TBM) show dramatic tissue, age, pattern and spectrum specificity". Mutation Research. 534 (1–2): 173–186. doi:10.1016/S1383-5718(02)00277-2. PMID 12504766.
  12. ^ Buettner VL, Hill KA, Halangoda A, Sommer SS (1999). "Tandem-base mutations occur in mouse liver and adipose tissue preferentially as G:C to T:A transversions and accumulate with age". Environmental and Molecular Mutagenesis. 33 (4): 320–324. doi:10.1002/(SICI)1098-2280(1999)33:4<320::AID-EM9>3.0.CO;2-S. PMID 10398380.
  13. ^ Väli U, Brandström M, Johansson M, Ellegren H (January 2008). "Insertion-deletion polymorphisms (indels) as genetic markers in natural populations". BMC Genetics. 9: 8. doi:10.1186/1471-2156-9-8. PMC 2266919. PMID 18211670.
  14. ^ Erixon P, Oxelman B (January 2008). Volff JN (ed.). "Whole-gene positive selection, elevated synonymous substitution rates, duplication, and indel evolution of the chloroplast clpP1 gene". PLOS ONE. 3 (1): e1386. Bibcode:2008PLoSO...3.1386E. doi:10.1371/journal.pone.0001386. PMC 2148103. PMID 18167545.
  15. ^ Pereira F, Carneiro J, Matthiesen R, van Asch B, Pinto N, Gusmão L, Amorim A (December 2010). "Identification of species by multiplex analysis of variable-length sequences". Nucleic Acids Research. 38 (22): e203. doi:10.1093/nar/gkq865. PMC 3001097. PMID 20923781.
  16. ^ Nakamura H, Muro T, Imamura S, Yuasa I (March 2009). "Forensic species identification based on size variation of mitochondrial DNA hypervariable regions". International Journal of Legal Medicine. 123 (2): 177–184. doi:10.1007/s00414-008-0306-7. PMID 19052767. S2CID 10531572.
  17. ^ Taberlet P, Coissac E, Pompanon F, Gielly L, Miquel C, Valentini A, et al. (26 January 2007). "Power and limitations of the chloroplast trnL (UAA) intron for plant DNA barcoding". Nucleic Acids Research. 35 (3): e14. doi:10.1093/nar/gkl938. PMC 1807943. PMID 17169982.
  18. ^ Bai H, Cao Y, Quan J, Dong L, Li Z, Zhu Y, et al. (2013). "Identifying the genome-wide sequence variations and developing new molecular markers for genetics research by re-sequencing a Landrace cultivar of foxtail millet". PLOS ONE. 8 (9): e73514. Bibcode:2013PLoSO...873514B. doi:10.1371/journal.pone.0073514. PMC 3769310. PMID 24039970.
  19. ^ Zheng LY, Guo XS, He B, Sun LJ, Peng Y, Dong SS, et al. (November 2011). "Genome-wide patterns of genetic variation in sweet and grain sorghum (Sorghum bicolor)". Genome Biology. 12 (11): R114. doi:10.1186/gb-2011-12-11-r114. PMC 3334600. PMID 22104744.
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