hybridisationmedical dictionary

<molecular biology> The process of joining two complementary strands of DNA or one each of DNA and RNA to form a double-stranded molecule.

Technique in which single stranded nucleic acids are allowed to interact so that complexes or hybrids, are formed by molecules with sufficiently similar, complementary sequences. By this means the degree of sequence identity can be assessed and specific sequences detected. The hybridisation can be carried out in solution or with one component immobilised on a gel or, most commonly, nitrocellulose paper.

Hybrids are detected by various means: visualisation in the electron microscope, by radioactively labelling one component and removing noncomplexed DNA or by washing or digestion with an enzyme that attacks single stranded nucleic acids and finally estimating the radioactivity bound. Hybridisations are done in all combinations: DNA DNA (DNA can be rendered single stranded by heat denaturation), DNA RNA or RNA RNA.

In situ hybridisations involve hybridising a labelled nucleic acid (often labelled with a fluorescent dye) to suitably prepared cells or histological sections. This is used particularly to look for specific transcription or localisation of genes to specific chromosomes (FISH analysis).

<zoology> The mating of individuals from different species or sub-species.

(13 Oct 1997)