Dot blot
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Dot blot is a technique in molecular biology used to detect biomolecules. It replaces either Northern blot, Southern blot or Western blot. In dot blot the biomolecules to be detected are not separated by chromatography. Instead a mixture possibly containing the molecule to be detected is applied directly on a membrane as a dot. This is then immediately followed by detection by either nucleotide probes (Northern blot and Southern blot) or antibody (Western blot). The technique offers significant savings in time as chromatography and complex blotting procedure for the chromatography gel are not required. However, it offers no information on the size of the biomolecule. Furthermore, if two molecules of different sizes are detected, they will still appear as a single blot. Dot blot therefore can only confirm the presence or absence of a biomolecule or biomolecules which can be detected by the probes or the antibody.
