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The effect of the DUPLEXER™ reagent on patient’s DNA is to change its conformation, which allows accurate identification of:
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Normal patients |
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Those who are carriers of the disease, but who
are clinically normal |
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Those who have the particular genetic disease. |
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Gel picture shows the results from PAGE but other
methods, e.g. capillary electrophoresis, can be used. |
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Single nucleotide polymorphisms (SNPs) are the most
frequent type of genetic variation in the human genome. They account for more than 90% of all
differences between individuals. It is likely that these variable
patterns of SNPs will account for many of the complex phenotypic
characteristics found in humans. SNP analysis has the potential to predict
susceptibility to a variety of clinical conditions including cancer,
cardiovascular disease and mental illness and in making targeted drug
therapy a reality. Millions of SNPs have already been identified within the
human genome. SNPs are considered to be important genetic markers.
This is due to their abundance within the human genome and association
they may have with many genetic traits and disease susceptibility. SNPs
may be situated close together within a region of DNA and can be
inherited in different combinations or haplotypes. |
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Mutations are a class of SNP which create aberrant
proteins or differences in protein expression associated with classical inherited metabolic or other
diseases. Examples include: Cystic Fibrosis, Phenylketonuria, Sickle
Cell Disease and Von Willebrand’s Disease. |
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| Unlike many currently used DNA diagnostic tests, a single DUPLEXER™ reagent is capable of identifying single or multiple SNPs, and haplotypes. This is possible because of the unique design of the reagent. For many applications, this permits a substantial reduction in the number of tests required. Haplotyping is a great advantage because it is increasingly apparent that haplotypes, not genotypes, may be more relevant in disease and protein expression studies. Heteroduplex-based haplotyping results provide unequivocal evidence of the physical linkage of SNPs. |
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| The DUPLEXER™ reagent mimics regions of naturally-occurring disease genes but
differs from them due to the possession of multiple ‘identifiers’. These
identifiers are found adjacent to all or some of the SNPs within the DNA.
When human DNA PCR product (containing the SNPs in question) is mixed with the DUPLEXER™ reagent
under certain experimental conditions, it undergoes a
conformational change - the PCR product bends and becomes rigid - in a manner which
is specific to the SNP or mutation causing the disease.
A single DUPLEXER™ reagent possessing a combination of identifiers can cause
unique conformational changes to occur for single or clustered SNPs and
haplotypes. These changes are induced by heteroduplex formation and can
be detected on various instrument platforms. |
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AAT Pi*Z Gel showing induced heteroduplexes |
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Methylenetetrahydrofolate reductase showing induced heteroduplexes |
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Glycogen storage disease 1a Gel showing induced heteroduplexes |
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von Willebrand exon 19 Gel showing induced heteroduplexes |
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Canavan E285A/A305E Gel showing induced heteroduplexes |
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