The range of DNA changes detected in diagnostic genomics include 1) single-base changes that include normal variations (DNA polymorphisms such as SNPs) and DNA mutations, 2) deletions that can be small (the AF508 three-base-pair deletion in cystic fibrosis) or very large (some examples of a° thalassemia), 3) rearrangements, e.g., the flip-tip on the X chromosome leading to hemophilia A, 4) sizing of simple tandem repeats such as microsatellites or expansions in triplet repeats found in a number of neurological disorders, and 5) epi-genetic effects such as DNA methylation associated with gene silencing.
To detect these changes in DNA, four broad classes of DNA tests are used. These tests are based on 1) sizing, 2) hybridization, 3) sequencing, and 4) quantitation. For most DNA diagnostic assays, efficient and reproducible separation of DNA fragments and accurate sizing are key requirements. Traditionally, this has been undertaken by slab gel electrophoresis using polyacryl-amide or agarose. These electrophoretic techniques are slow, and the accuracy is limited if visual inspection is used for sizing. As well as being time consuming, the traditional electrophoretic approaches are less amenable to automation.
Capillary electrophoresis is now replacing slab gel electrophoresis because it is faster, more sensitive and reproducible, and allows greater flexibility in the design of diagnostic DNA assays. The modern DNA laboratory will utilize capillary electrophoresis in conjunction with robotics to ensure that diagnostic DNA tests are efficiently and accurately undertaken.
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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.