molecular hybridization, hybridization


molecular hybridization, hybridization

or

annealing

the artificial creation of duplex polynucleotide molecules (hybrids) by ‘annealing’ complementary single strands of nucleic acid together. Such techniques enable the estimation of complementarity between DNA/DNA, DNA/RNA and RNA/RNA polynucleotide chains (see COMPLEMENTARY BASE PAIRING). Hybridization can be used to detect specific nucleotide sequences if a labelled PROBE molecule, complementary to the desired sequence, is available. Hybridization can be carried out in different ways, for example: (i) in solution, where both single-stranded nucleic acid molecules are free in solution; (ii) on filters, where one of the nucleic acid molecules is immobilized on a filter (see NORTHERN TRANSFER, SOUTHERN TRANSFER) and the other is in solution, hybridization occurring on the filter; and (iii) in situ (see IN SITU HYBRIDIZATION). Hybridization can be carried out under conditions of high stringency, which allow only precisely homologous sequences to hybridize, without any MISMATCH OF BASES being tolerated in the hybrid; or under conditions of low stringency, which allow less homologous sequences to hybridize so that some mismatching of bases can be tolerated.