[A method of competitive dot hydridization for genotyping influenza A viruses]

A new method for genetic typing of influenza viruses using molecular hybridization of DNA-RNA was developed which consisted in addition to the hybridization solution, apart from the radioactively labeled probe, of RNA of a virus with known gene homologous to the plasmid DNA used as the probe but belonging to a different serosubtype of influenza A virus, other than cloned kDNA, (within the range of H1N1, H2N2, and H3N2). This competitive RNA (RNAc) is added in considerable excess with regard to both molecular probe and to RNA immobilized on the filter. Therefore hybrids of molecular probe DNA with RNAc are rapidly formed from which RNAc may be replaced only by those bRNA immobilized on the filter whose homology to the probe is higher than that of RNAc.