Early studies demonstrated that mismatched bases became chemically reactive. Mismatched guanine and thymine react with the compound carbodiimide, and mismatched cytosine reacts with hydroxylamine (NH2OH). Mismatched thymine also reacts with osmium tetroxide (OsO4), potassium permanganate/tetramethylammo-nium chloride (KMNO^TMAC), and potassium per-manganate/tetraethylammonium chloride (KMNO4/ TEAC). These chemical reactions were exploited in the development of the mismatch detection techniques, chemical cleavage of mismatch, and the carbodiimide method. Chemical cleavage of mismatch or chemical mismatch cleavage (CMC) was developed for use in the detection of single-base mismatches in cloned DNA, and with the advent of PCR, was employed to the screening of genomic DNA and mRNA. Chemical cleavage of mismatch is based upon the detection of base mismatches in double-stranded DNA hybrids called heteroduplexes. These heteroduplexes are generated by mixing probe (wild type) and target (patient) DNA. When the sequence is different in the target compared to the probe, which can be caused by mutation or polymorphism, the usual Watson-Crick base pairing is disrupted. These free bases can then be chemically modified whereby they become substrates for piperidine cleavage of the DNA strand at or adjacent to the mismatch. Probe and/or target DNA can be fluorescently or radioactively labeled with the subsequent detection of cleavage products using either an automated fluorescent analyzer or autoradiography in conjunction
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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.