Adaptations

The use of denaturing HPLC systems to resolve hetero-duplexes from homoduplexes has been reported for many gene mutations and has been discussed in another chapter. Heteroduplex analysis has been adapted for the detection of specific mutations in numerous conditions including von Willebrand's disease, PKU, hemochromatosis, and rifampicin resistance in tuberculosis.[24-27] As discussed above, test samples which are heterozygous for a mutation provide for a straightforward preparation of DNA heteroduplexes without the need for annealing to a reference sample, an additional step which can be time-consuming. For single-base substitutions the conforma-tional change is often relatively small, but to enhance this difference for specific mutations a special fragment, termed a universal heteroduplex generator (UHG), has been developed.[28] This synthetic sequence is similar to genomic sequence but contains specific substitutions or indels at nucleotide positions corresponding to and contiguous with known mutation sites within the genomic DNA. A PCR-amplified test fragment is mixed with the UHG, denatured, and then slowly cooled to form a heteroduplex which is then electrophoresed on a suitable gel (Fig. 3). If the test fragment contains a point mutation then the heteroduplex will contain both a bulge and bubble, and, consequently, will migrate much more slowly than a heteroduplex without the mutation or a homoduplex.

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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