Dna Mutation Detection

Capillary gel electrophoresis is ideal for detecting DNA fragment sizes that include small or large deletions, insertions, allele-specific amplification fragments, and oligonucleotide ligation or primer extension products. For example, a common mutation in the genetic disorder cystic fibrosis is AF508 mutation. This involves a 3-bp deletion in the CFTR gene. To detect this deletion by CGE, we label the forward primer with FAM, a fluorophore that emits a blue light spectrum on laser excitation. After PCR amplification, the product is separated on CGE. The mutant, shorter allele emits a blue fluorescence at 91 bp, compared with the normal allele that produces a peak of blue fluorescence at 94 bp. The two peaks are easily distinguishable. As well as separating wild type and mutant alleles on the basis of size, it is possible to distinguish point mutations on the basis of color. This is illustrated by SNP analysis (Fig. 2a).

For DNA sequencing, the four terminating dideoxynu-cleotides are each labeled with different flurophores. Each time a ddNTP is incorporated into the extending product, it results in termination of product extension, with the terminal nucleotide identified by its fluorescent label. The final product is composed of a heterogeneous population with different-sized products that can be distinguished by their various spectral emissions. With the fluorescent labeling, the entire reaction can be run in the same capillary; that is, multiplexing is possible, which was also illustrated in the earlier SNP example.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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