作者: C. Luo , T. Morishita , K. Satou , Y. Tateno , K. Nakajima
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摘要: Phylogenetic analysis was carried out for genes encoding hemagglutinin (HA) (24 new and 25 previously reported sequences) nonstructural proteins (NS) (22 14 of influenza B virus isolates obtained from 1940 to 1999. Two antigenically genetically distinct HA lineages are presently known exist. Divergence into these two estimated have occurred around 1969. NS revealed that their phylogenetic relationships were not linked the but suggested reassortment viral between viruses had occurred. In addition which observed. Viruses isolated after 1997 formed own lineage in combination with B/Houston/84 while other 1973 1995 comprised lineage.