Tandem repeat

Tandem repeat

Tandem repeats occur in DNA when a pattern of two or more nucleotides is repeated and the repetitions are directly adjacent to each other. [1]

Contents

Example

An example would be:

A-T-T-C-G-A-T-T-C-G-A-T-T-C-G

in which the sequence A-T-T-C-G is repeated three times.

Terminology

When between 10 and 60 nucleotides are repeated, it is called a minisatellite. Those with fewer are known as microsatellites or short tandem repeats.

When exactly two nucleotides are repeated, it is called a "dinucleotide repeat" (for example: ACACACAC...). The microsatellite instability in hereditary nonpolyposis colon cancer most commonly affects such regions.[2]

When three nucleotides are repeated, it is called a "trinucleotide repeat" (for example: CAGCAGCAGCAG...), and abnormalities in such regions can give rise to trinucleotide repeat disorders.

When the number is not known, variable, or irrelevant, it is sometimes called a variable number tandem repeat (VNTR). MeSH classifies variable number tandem repeats under minisatellites.[3]

Uses

Tandem repeat describes a pattern that helps determine an individual's inherited traits.

Tandem repeats can be very useful in determining parentage. Short tandem repeats are used for certain genealogical DNA tests.

DNA is examined from microsatellites within the chromosomal DNA. Minisatellite is another way of saying special regions of the loci. Polymerase chain reaction (or PCR) is performed on the minisatellite areas. The PCR must be performed on each organism being tested. The amplified material is then run through electrophoresis. By checking the percentage of bands that match, parentage is determined.

In the field of Computer Science, tandem repeats in strings (e.g. DNA sequences) can be efficiently detected using suffix trees or suffix arrays.

Studies in 2004 linked the unusual genetic plasticity of dogs to mutations in tandem repeats.[4]

See also

References

  1. ^ MeSH Tandem+Repeat
  2. ^ Oki, E.; Oda, S.; Maehara, Y.; Sugimachi, K. (1999). "Mutated gene-specific phenotypes of dinucleotide repeat instability in human colorectal carcinoma cell lines deficient in DNA mismatch repair". Oncogene 18 (12): 2143–2147. doi:10.1038/sj.onc.1202583. PMID 10321739.  edit
  3. ^ MeSH Variable+Number+of+Tandem+Repeats
  4. ^ Pennisi, E. (Dec 2004). "Genetics. A ruff theory of evolution: gene stutters drive dog shape". Science 306 (5705): 2172. doi:10.1126/science.306.5705.2172. ISSN 0036-8075. PMID 15618495.  edit

External links


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Look at other dictionaries:

  • tandem repeat — Two (or more) contiguous identical DNA sequences. The orientation can be either head to tail, or head to head. Synonyms: tandem array, sequence tandem repeat …   Glossary of Biotechnology

  • Tandem repeat locus — Variable number of tandem repeat locus (VNTR locus) is any DNA sequence that exist in multiple copies strung together in various tandem lengths …   Wikipedia

  • tandem repeat — tan·dem repeat tan dəm n any of several identical DNA segments lying one after the other in a sequence compare LONG TERMINAL REPEAT * * * 1. arrangement of two or more copies of a nucleotide sequence adjacent to each other within a segment of DNA …   Medical dictionary

  • tandem repeat — noun Date: 1973 any of several identical DNA segments lying one after the other in a sequence …   New Collegiate Dictionary

  • Variable number tandem repeat — A Variable Number Tandem Repeats (or VNTR) is a location in a genome where a short nucleotide sequence is organized as a tandem repeat. These can be found on many chromosomes, and often show variations in length between individuals. Each variant… …   Wikipedia

  • Short tandem repeat — A short tandem repeat (STR) in DNA is a class of polymorphisms that occurs when a pattern of two or more nucleotides are repeated and the repeated sequences are directly adjacent to each other. The pattern can range in length from 2 to 10 base… …   Wikipedia

  • variable number of tandem repeat locus — variable number of tandem repeat locus. См. локус с варьирующим числом тандемных повторов. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • sequence tandem repeat — Abbreviation: STR See: tandem repeat …   Glossary of Biotechnology

  • Tandem repeat sequences — Multiple copies of the same DNA base sequence on a chromosome; used as a marker in physical mapping of the chromosome …   Medical dictionary

  • Short Tandem Repeat — Short tandem repeats sind repetitive DNA Elemente und gehören zu den Satelliten DNAs. Als Short tandem repeats (kurz STR, von englisch: Short kurz, Tandem im Sinne von hintereinander, Repeat Wiederholung) wird in der Genetik die Wiederholung… …   Deutsch Wikipedia

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