Lindstrom Stephen E, Cox Nancy J, Klimov Alexander
Influenza Branch, MS-G16, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Virology. 2004 Oct 10;328(1):101-19. doi: 10.1016/j.virol.2004.06.009.
Phylogenic analysis of all gene segments of human H2N2 viruses isolated from 1957 to 1968 was undertaken to better understand the evolution of this virus subtype. Human H3N2 viruses isolated from 1968 to 1972 were also examined to investigate genetic events associated with their emergence in humans and to identify the putative H2N2 ancestral virus. All gene segments of human H2N2 viruses demonstrated divergent evolution into two distinct clades (I and II) among late H2N2 isolates. All gene segments of 1968 H3N2 viruses that were retained from human H2N2 viruses were most similar to clade I H2N2 genes. However, genes of both clades were found among H3N2 isolates of 1969-1971. Unique phylogenic topologies reflected multiple reassortment events among late H2N2 or H3N2 viruses that resulted in a variety of different genome constellations. These results suggest that H2N2 viruses continued to circulate after 1968 and that establishment of H3N2 viruses in humans was associated with multiple reassortment events that contributed to their genetic diversity.
对1957年至1968年分离出的人类H2N2病毒的所有基因片段进行了系统发育分析，以更好地了解该病毒亚型的进化。还对1968年至1972年分离出的人类H3N2病毒进行了检测，以调查与其在人类中出现相关的基因事件，并确定假定的H2N2祖先病毒。人类H2N2病毒的所有基因片段在晚期H2N2分离株中表现出趋异进化，形成了两个不同的进化枝（I和II）。从人类H2N2病毒中保留下来的1968年H3N2病毒的所有基因片段与进化枝I的H2N2基因最为相似。然而，在1969 - 1971年的H3N2分离株中发现了两个进化枝的基因。独特的系统发育拓扑结构反映了晚期H2N2或H3N2病毒之间的多次重配事件，这些事件导致了多种不同的基因组组合。这些结果表明，H2N2病毒在1968年后继续传播，并且H3N2病毒在人类中的建立与多次重配事件有关，这些事件促成了它们的遗传多样性。
