VNTRs repeats

Variable Number of Tandem Repeats (VNTR) Repeating element in DNA that is tens to hundreds of base pairs long also known as minisatellite or long tandem repeat. 

Variable numbers of randomly repeated (VNTR) units are one common type of insertion that results in an RFLP. The VNTRs can be inherited, in which case they are useful in estabhshing genetic association with a disease in a family or kindred or they can be unique to an individual and thus serve as a molecular fingerprint of that person. 

Kasai K, Nakamura Y and White R 1990) Amplification of a variable number of tandem repeats (VNTR) locus (pMCTii8) by the polymerase chain reaction (PCR) and its application to forensic science. ] For Sci 35 1196-1200. 

Although less common than SNPs, another type of genetic polymorphism is the variable nucleotide tandem repeat (VNTR), also called microsatellite [65]. 

Ethnic variation in allele frequencies can lead to important differences in disease susceptibility, outcome and drug metabolism [68, 69]. In addition to single nucleotide polymorphisms, variable number of tandem repeat (VNTR) regions have been shown to have functional significance. 

Expansion of repetitive sequences (minisateflites or VNTRs, variable number of tandem repeats) within the DNA... 

Minisatellites-the repeated unit typically ranges from 20 to 70 bp, and the length of the entire repeat may reach 20 kb. This is the class most often referred to as VNTRs and contributes to RFLP patterns on Soulhem blots. 

VNTRs (variable number of tandem repeats). These polymorphisms are the result of varying numbers of minisatellite repeats in a specific region of a chromosome. The repeat units typically range in size from 20 to 70 bases each. The repeat is flanked on both sides by a restriction site, and variation in the number of repeats produces restriction fragments of varying size. 

The dopamine D -like receptor polymorphisms include SNPs, variable-number tandem repeats (VNTRs), and splice variants (58,59). The polymorphic forms of the dopamine D receptor, for example, manifest as variable numbers of 48-bp repeat sequences (denoted D j to D., ) (49). 

The initial VNTRs were several hundred nucleotide units long requiring extended laboratory periods for the various segments to separate on the gel. Today, most tests employ shorter, 3 5 nucleotides long, VNTRs that allow for more rapid movement on the gel, resulting in faster and less costly results. It also allows for the production of a greater number of sequences that are looked at, and hence a greater ability to match or not match the results. These shorter sequences are called short tandem repeats (STRs). 

Pattern of fragments varies from one person to another according to where and how many repeated units of the VNTR are located on their genomes, —i—— J... 

Restriction fragment length polymorphism (RFLP) of variable number tandem repeats (VNTR) For each person, a pair of homologous chromosomes is shown. 

Forensic analysis of DNA samples DNA fingerprinting by means of PCR has revolutionized the analysis of evidence from crime scenes. DNA isolated from a single human hair, a tiny spot of blood, or a sample of semen is sufficient to determine whether the sample comes from a specific individual. The DNA markers analyzed for such fingerprinting are most commonly short tandem repeat polymorphisms (STRs). These are very similar to the VNTRs described previously (see p. 455), but are smaller in size. [Note Verification of paternity uses the same techniques.]... 

The VNTRs or minisatellites of the human genome may be repeated 100 times or more in different persons. Many VNTRs, numbering in the thousands, are well characterized. Restriction fragment analysis will produce different size fragments proportional to the number of repeats in the VNTR. Where the identification of traits has been slowed for lack of a sufficient number of suitable genetic markers, the use of VNTRs should alleviate this constraint.(24)... 

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