Microarray Hybridization

Microarrays allows the identification of organisms in an ecological sample by hybridizing DNA extracted from the sample to a set of known DNA specimens arrayed on a solid support, usually a microscope slide (reviewed in Call et al. 2003). The sample DNA, or more usually PCR product derived from it, is labeled with a fluorophore so that the specific sites of hybridization on the microarray can be visualized and the intensity of the hybridization signal quantified. The method is conceptually identical to Southern hybridization of a dot blot, but technological innovations allow thousands of known DNA samples to be arrayed on a single microscope slide and many such slides to be produced in a single batch at low cost.