noun, plural: variable number of tandem repeats
(molecular biology) A DNA segment in the genome that consists of short nucleotide sequences organized as a tandem repeat
Tandem repeats are repeated nucleotide sequences in which the copies lie adjacent to each other. It may be repetition(s) of one or more nucleotides. For example, CG CG CG CG CG is a tandem repeat wherein the sequence CG is repeated five times. Examples of tandem repeats are satellite DNA, microsatellite, and minisatellite. The microsatellites and the minisatellites make up the so-called variable number of tandem repeats (VNTR). A variable number of tandem repeat is a short stretch of DNA consisting of tandemly repeating nucleotide sequence.
Microsatellite repeats are tandem arrays of repetitive DNA sequences. They are similar to minisatellites in being a stretch of DNA consisting of tandem repeats. However, microsatellites are shorter than minisatellites. The typical length of a microsatellite is about one to six base pairs, repeated about five to fifty times. As for the minisatellite repeat, the typical length is about ten to 60 base pairs repeated about five to fifty times. Microsatellites occur in the arms of certain chromosomes. Minisatellites are common in the in the telomeres and centromeres of the chromosomes.
Analysis of VNTRs is essential in forensics and DNA fingerprinting.