VNTR sequences

Answer C. VNTR sequences are amplified using a PCR and analyzed by gel electrophoresis. Although RPLP analysis could potentiaDy be used for this purpose, it is not the method of choice. 

Variable-number tandem repeats (VNTRs) sequences of bases that are repeated in tandem almost without change up to 40 copies ... 

Another reason for hypothesizing that VNTR sequences may be useful in detecting increased mutation rates is that a few intriguing studies have now... 

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

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). 

The different alleles at a minisatellite locus are thought to vary in the number of repeats of the consensus sequence, hence the name variable number of tandem repeats (VNTR) locus.7 For some human VNTR loci... 

In conclusion, these results further open the door to the creation of numerous minisatellite probes to survey for VNTR loci. Such probes can be used not only for restriction fragment length polymorphism (RFLP) analyses of the many biological applications outlined in the introduction, but they can also be employed to screen cloned libraries with the ultimate goal of determining the sequences flanking VNTR loci. The latter information provides perhaps the most accurate and rapid means of utilizing the variation at such loci via the PCR analysis of alternate alleles. 

In the mid-1980s, these techniques were replaced by direct analysis of the DNA polymorphisms. The first of such techniques, developed by Alec Jeffries utilized multilocus DNA probes. This technique is known as the restriction fragment length polymorphism (RFLP) testing. RFLP techniques are based on variable number of tandem repeats (VNTR), which are sequences of 10 to 60 bp (base pairs) of length, that lie adjacent to each other in the same chromosomal orientation (minisatellites). 

Giycopeptide vaccine recentiy described by Kunz and co-workers comprising the immunodominant (PDTRP) sequence of the VNTR domain of MUC1, adorned with the sT t antigen and connected to a T-ceii epitope (OVA323 -339) known to be presented to MHC ciass ii moiecuies... 

A phase I clinical trial was conducted with a MUCl peptide containing 3 VNTR domains and additional MUCl flanking sequence (AHGVTSA[3 x PDTRPAPGSTAPPAHGVTSA]PESR-... 

Some DNA alterations involve sequence insertions, deletions, rearrangements, and changes in the number of repeat sequences (such as STRs and VNTRs). If these alterations reside within a fragment that can be amplified reliably by PCR, then variation in the length of the amplified fragment wili indicate these structural alterations. Enzyme digestion is... 

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