Variable number tandem repeat
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A variable number tandem repeats (VNTR) is a short nucleotide sequences ranging from 14 to 100 nucleotides long that is organized into clusters of tandem repeats, usually repeated in the range of between 4 and 40 times per occurrence. Clusters of such repeats are scattered on many chromosomes. Each variant is an allele and they are inherited codominantly.
Coupled with Polymerase chain reactions, VNTRs have been very effective in forensic crime investigations. When VNTRs are cut by restriction enzymes and the results are visualized with a gel electrophoresis, a pattern of bands unique to each individual is produced. The number of times that a sequence is repeated varies between different individuals and between maternal and paternal loci of an individual. The likelihood of two individuals having the same band pattern is near impossible.