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What is FISH?
The Fluorescent in situ hybridization technique (FISH) is used to visualize the chromosomal location of a specific DNA (or RNA). The probe is labeled with a flourescent dye. It is then added to a chromosomal preparation from the species of interest. After a sufficient time for annealing to occur, the chromosomes are viewed using a fluorescent microscope. The probe will hybridize to the chromosome carrying the sequence of interest. If the species has been characterized cytogenetically, the marker can be assigned to the appropriate chromosome. Because this technique uses a fluorescent probe it is called fluorescence in situ hybridization or FISH. It has also been called chromosome painting.
Observation of the hybridized sequences is made with an epifluorescence microscope. The white light of the source lamp is filtered so that only the relevant wavelengths for excitation of the fluorescent molecules arrive onto the sample. Emission of the fluorochromes happens in general at larger wavelengths, which allows to distinguish between excitation and emission light by mean of another optical filter. One thus sees bright colored signals on a dark background.
With a more sophisticated filter set, it is possible to distinguish between several excitation and emission bands, and thus between several fluorochromes, which allows observation of many different probes on the same strand.
FISHView
FISHView® is Applied Spectral Imaging's fully-automated image acquisition and analysis system for FISH. FISHView
is one of ASI's CytoLabView modules for Cytogenetics. Other related products for FISH are: Manual Counting, SpotCView, MultiStain and SPOTScan.
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