The variability of genes of influenza A (H3N2) virus strains isolated in the G.D.R. during the 1970-1978 epidemic seasons.

Gene variability of all influenza A virus strains (H3N2) isolated in the G.D.R. during the epidemic seasons of 1970-1978 was investigated by cRNA:vRNA hybridization. From 1970 through 1975 a gradual smooth variability of the majority of genes and moderate heterogeneity in gene homology of the isolates were observed. From 1975 through 1977 the genome variability was more profound and the isolates differed from one another in gene homology. In 1978 the variability became less pronounced again. Quantitative evaluation of the variability for individual genes gave the following results: 0.4% nucleotides per year for genes, 1, 2, 3 (P proteins), 1.4% for gene 4 (HA), 0.1% for gene 5 (NP), 1.0% for gene 6 (NA), 0.1% for gene 7 (M) and 0.4 for gene 8 (NS).