RT Journal Article SR Electronic(1) A1 Nakao, Haruhisa A1 Nakajima, Katsuhisa A1 Nakajima, SetsukoYR 1993 T1 Location on the evolutionary trees of the non-structural protein (NS) and neuraminidase (NA) genes of late human influenza A (H2N2) viruses: parental viruses of the NS and NA genes of Hong Kong influenza A (H3N2) viruses JF Journal of General Virology, VO 74 IS 8 SP 1667 OP 1672 DO https://doi.org/10.1099/0022-1317-74-8-1667 PB Microbiology Society, SN 1465-2099, AB The nucleotide sequences of the non-structural protein (NS) and neuraminidase (NA) genes of human influenza A (H2N2) viruses isolated in 1967 and 1968 in Europe, Asia and North and South America were located on evolutionary trees in order to identify the parental virus of Hong Kong influenza A (H3N2) viruses, which appeared in the human population in 1968. From the evolutionary trees, the H2N2 viruses isolated during the 1967 to 1968 period were divided into two groups. Group I includes the A/Tokyo/3/67, A/Hachioji/1/67, A/Perg/1/68, A/Cordoba/522/67, A/Texas/2/68 and A/Berkeley/1/68 viruses, whereas group II includes the A/Georgia/1/67, A/England/10/67 and A/Poland/6/67 viruses. The NS and NA genes of Hong Kong H3N2 viruses isolated in 1968 were genetically closer to those of group II viruses and closest to those of A/Poland/6/67., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-74-8-1667