Spectral karyotyping was first described in 1996 by Schrock et al. Metaphase chromosomes are hybridized with the commercially available SKY probe mixture, consisting of 24 chromosome-specific probes. Each probe is differentially labeled with up to four different fluorophores. In contrast to m-FISH, only one image is captured. A fluorescence microscope, using a camera coupled to a spectral color analysis system, analyzes the spectrum from 450 to 750 nm for each pixel in the image.
In this way, each (part of a) chromosome can be recognized by its own distinct color spectrum. With dedicated image analysis software, a final karyogram image is created showing all chromosomes with their unique spectral color (or false color if preferred), allowing easy identification of structural changes such as insertions and translocations. In addition, a DAPI image is captured to assess the band position of possible breakpoints (Fig. 2).
Because in SKY analysis the direct spectral image is used, the problem of flaring in the false color image, resulting in the suggestion of additional insertions, can be overcome. Similar to m-FISH, SKY does not detect inversions or duplications (unless there are obvious changes in centromere position or chromosome size) because these do not lead to a translocated color. In addition, small translocated chromosome parts (less than 1-3 Mbp) may be difficult to determine. Notwithstanding these limitations, several spectral karyotyping studies have shown its superior possibilities over conventional cytogenetic analyses. Comparisons showed up to 50% false interpretations with conventional cytogenetic analysis.1-5,6-1 With the help of data from numerical chromosomal analyses, e.g., with array CGH, the interpretation
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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.