The parallel development of fluorescent probes and of high-throughput thermal cyclers capable of continuously measuring fluorescence has fueled the emergence of real-time polymerase chain reaction (RT-PCR) as the diagnostic method of choice to accurately detect and quantify the occurrence of a specific DNA sequence in a given sample (see chapters on Real-Time PCR, Quantitative Real-Time PCR, Real-Time PCR platforms). The uses of RT-PCR range from gene copy number determination to RNA expression profiling to allelic discrimination, to name a few. Regardless of the chemistry used in RT-PCR, specific hybridization of the probe to the target DNA sequence ultimately results in the production of a specific fluorescent signal that can be measured in the reaction vessel directly, without any post-PCR processing of the samples (such as performing agarose gel electrophoresis of the reaction, or indeed even opening the reaction vessel). The major fluorescence detection technologies used in RT-PCR are described elsewhere in this encyclopedia, including DNA binding fluorophores, linear oligoprobes, hairpin oligoprobes (such as molecular beacons), scorpion probes, and hybeacons. The TaqMan assay has the privilege of being the most widely used fluorescence detection methodology for RT-PCR, and also one of the first ones to be developed. The purpose of this chapter is to introduce the principle behind the TaqMan assay, and to discuss different parameters in the design of TaqMan oligoprobes (also referred to as 5' nuclease oligoprobes).
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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.