Procedures for characterisation of the genetic material of candidate vaccine strains.

Two procedures for characterising the genomes of recombinant influenza viruses are described. The first of these involves ribonuclease T4 oligonucleotide fingerpart analysis of separated viral RNAs labelled either in vivo or in vitro and the second utilises polyacrylamide gel electrophoresis to identify the double-stranded molecules formed by hybridisation between the complementary and virion RNAs of two viruses. Although the latter method is more suitable for routine screening purposes, both procedures are suitable for distinguishing between equivalent RNA components of closely related viruses.