Abstract
Polyacrylamide gel electrophoresis of the RNA of influenza A/PR/8/34 (H0N1) and A/Hong Kong/8/68 (H3N2) viruses and recombinant viruses derived from them revealed that each contains eight RNA segments, the fourth of which codes for hemagglutinin. (The largest RNA of the segmented genome is counted as band 1.) The neuraminidase gene was identified as the sixth segment in the RNA pattern of influenza A/PR8 virus and as the fifth segment of A/Hong Kong virus. The molecular weights of the RNAs for the hemagglutinin and the neuraminidase genes lie in the range of 600,000-700,000.