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In this article we will discuss about the Fluorescence Detection of DNA and RNA.
Fluorescence detection of DNA and RNA is a frequently followed task in most of the genetic engineering laboratories. Although low levels cheaper and quicker to use than other detection methods. Some of the newer DNA detection methods use fluorescence, chemical tagging and hybridization.
Fluorescence occurs when a molecule absorbs light of one wavelength and emits light of lower energy at a longer wavelength (Fig. 3.9). Detection of fluorescence requires both a beam of light to excite the dye and a photo-detector to detect the fluorescent emission.
Fluorescent dyes can be attached to DNA molecules, and modern automated methods for DNA sequencing make use of such fluorescent tagging. In this case, each of the nucleotide bases is labelled with a different fluorescent dye.
As each of the bases passes through the sequencing machine, a laser activates the dye which fluoresces by emitting light of lower wavelength. A detector records the wavelength of emitted light, and translates the data to give the identity of each passing base. The nucleotide sequence is printed for the researcher.