Deletion/insertion detection

Fig. 14. Examples of homogeneous hybridization assay methods (F luminophore, Q quencher, D donor, A acceptor). Thick lines represent DNA strands. Open circles on DNA strands indicate a SNP/mutation site for Molecular Beacon and insertion/deletion sites for dual FRET probe and dual FRET Molecular Beacon when these methods are applied to SNP/mutation typing or deletion/insertion detection. The solid circle on die strand indicates the complementary site.

Gene mutations point mutations, small deletions/ insertions. Detection of gene mutations in the loci bacterial reporter gene. Main steps are ... 

Acetylcholinesterase inhibition has been widely used for pesticide detection [88-94], but less exploited than protein phosphatase inhibition for cyanobacterial toxin detection. Nevertheless, the anatoxin-a(s) has more inhibition power than most insecticides, as demonstrated by the higher inhibition rates [95]. In order to detect toxin concentrations smaller than usually, mutant enzymes with increased sensitivity were obtained by genetic engineering strategies residue replacement, deletion, insertion and combination of mutations. Modifications close to the active site, located at the bottom of a narrow gorge, made the entrance of the toxin easier and enhanced the sensitivity of the enzyme. 

Large-scale deletions, insertions, and tandem duplications of mtDNA are usually not found in blood cells, and the proportions of mtDNA with point mutations in blood cells are generally lower than those in muscle of patients with mitochondrial disease (PI, W5). Thus, the absence of mtDNA mutation in blood samples cannot be used to exclude mitochondrial disease (L7, PI). On the other hand, higher levels of mutant mtDNA are usually found in postmitotic tissues such as cardiac and skeletal muscles and skin tissue of patients. Large-scale deletions or point mutations of mtDNA are generally detectable in muscle biopsies of about 70% of patients with mitochondrial disease (L7, PI). Some of these patients are affected by mutations in nuclear DNA. Other, unknown mutations in mtDNA or nuclear DNA are present in the rest of the patients. 

Tian H, Brody LC, Landers JP. Rapid detection of deletion, insertion, and substitution mutations via heteroduplex analysis using capillary- and microchip-based electrophoresis. Genome Res 2000 10 1403-1413. 

The Lesch-Nyhan (LN) syndrome of mental retardation, hyperuricemia and self-mutilation is an X-linked disease of man resulting from a deficiency of the enzyme hypoxanthine-guanine phosphoribosy 1-transferase (HPRT) (1). It is known that a number of LN patients exhibit no enzyme activity and no crossreacting antigen (1,2) mutation in these patients may be due to substantial deletions or insertions detectable by Southern analysis We have undertaken an initial survey of LN patients looking for major gene alterations detectable by Southern analysis our findings constitute the body of this report ... 

In particular, the repetition, deletion, insertion, and incorrect sequence are addressed by the counter, corruption by the CRC checksum, addressing faults by the data ID. In addition to this, the real-time properties of AUTOSAR in combination with periodically sending messages enable detection of not receiving new data on the bus. Timeouts are therefore represented by either no new data available or by receiving new data with the same counter as the previously received valid data. 

A similar analysis could be made for a number of other diseases. Point mutations are usually defined by sequencing the gene in question, though occasionally, if the mutation destroys or creates a restriction enzyme site, the technique of restriction fragment analysis can be used to pinpoint the lesion. Deletions or insertions of DNA larger than 50 bp can often be detected by the Southern blotting procedure. 

On replication, insertion or deletion of bases may occur. Chain scission and chromosome breaks are also possible. Quinacrine is useful in human cytogenetics, since it intercalates significantly into the heterochromatin of the Y chromosome, making it fluoresce and rendering it identifiable cytologically. Detection of the Y chromosome is important in prenatal sex determination. Other dyes present in our environment are potentially mutagenic. For example, some hair dyes were shown to be mutagenic for E. coli. 

Polymorphism A common (i.e., at least 1% prevalence of the minor allele in the population) sequence variation observed in an individual at a polymorphic site. Polymorphisms include nucleotide substitutions, insertions, deletions and microsatellites. They may be functional or silent, i.e., they do not result in detectable differences in gene expression or protein function. 

---