ABSTRACT
In filter hybridization, single-stranded DNA or RNA is bound to an inert support in such a way that it is prevented from reacting with itself, but is available to form hybrids with single-stranded nucleic acid added in solution. The gel is treated with alkali to denature the DNA and a filter is placed over the gel. Northern blots are similar to Southern blots except that the nucleic acid being analyzed is RNA instead of DNA. The probes are often cloned genes, so that information is obtained on expression of genes and on the size and relative amounts of transcripts. Dot blots are well-suited to analysis of many samples at once and have the added advantage that it is easy to prepare replicate filters. This allows filter-bound sequences to be analyzed under different conditions, for example, with different probes or with different hybridization and washing conditions.
