Buonagurio D A, Nakada S, Fitch W M, Palese P
Virology. 1986 Aug;153(1):12-21. doi: 10.1016/0042-6822(86)90003-6.
The nucleotide sequences of nonstructural protein (NS) genes of human influenza C viruses isolated between 1947 and 1983 were determined and compared. Assuming constant evolutionary rates, the extent of nucleotide differences among NS genes does not correspond to the isolation years of the strains. This suggests that more than one gene lineage is present in the population. Furthermore, examination of the eight C virus NS gene sequences by the maximum parsimony method (W. M. Fitch, 1971, Syst. Zool. 20, 406-416) yielded phylogenetic trees that were grossly different from those obtained using the hemagglutinin genes for the same eight isolates. This result is compatible with the idea of reassortment of genes in nature across lineages of influenza C viruses. The sequence analysis also suggests that nucleotide substitutions occur at a lower rate in the C virus NS genes than in influenza A virus NS genes.
测定并比较了1947年至1983年间分离出的人C型流感病毒非结构蛋白（NS）基因的核苷酸序列。假设进化速率恒定，NS基因之间的核苷酸差异程度与毒株的分离年份不相符。这表明该种群中存在不止一个基因谱系。此外，通过最大简约法（W.M.菲奇，1971年，《系统动物学》20卷，406 - 416页）对8个C型病毒NS基因序列进行分析，得到的系统发育树与使用相同8个分离株的血凝素基因所得到的系统发育树有很大差异。这一结果与C型流感病毒不同谱系间基因在自然条件下发生重配的观点相符。序列分析还表明，C型病毒NS基因中的核苷酸替换率低于甲型流感病毒NS基因中的核苷酸替换率。
