The evolutionary dynamics of human influenza B virus
The evolutionary dynamics of human influenza B virus
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DOI：
10.1007/s00239-008-9119-z
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发表时间：
2008-06-01
影响因子：
3.9
通讯作者：
Holmes, Edward C.
中科院分区：
文献类型：
--
作者：
Chen, Rubing;Holmes, Edward C.
尽管A型和B型流感病毒具有密切的系统发育关系，但它们在人类中表现出重大的流行病学差异，后者既不常见，也不常与严重疾病相关。然而，目前还不清楚是什么过程决定了B型流感病毒的进化动力学，以及甲型流感病毒和B型流感病毒在进化尺度上如何相互作用。为了解决这些问题，我们使用分离日期（天）的完整基因组序列推断人流感B病毒的系统发育史。通过比较所有8个病毒片段的系统发育模式，我们确定了30年采样期内片段重配的发生。核苷酸替换率和选择压力的分析显示，零星发生的适应性进化，最显着的是在病毒血凝素和兼容的抗原漂移的行动，但较低的整体和非同义核苷酸替换率相比，甲型流感病毒。总的来说，这些结果使我们提出了一个模型，其中抗原性不同的“Yam88”和“Vic87”流感病毒B谱系内和之间的进化变化是群体免疫变化的结果，重配不断产生新的遗传变异。此外，我们认为与甲型流感病毒的相互作用可能是塑造乙型流感B病毒进化动力学的核心，促进了Vic87和Yam88谱系之间的优势转移。
Despite their close phylogenetic relationship, type A and B influenza viruses exhibit major epidemiological differences in humans, with the latter both less common and less often associated with severe disease. However, it is unclear what processes determine the evolutionary dynamics of influenza B virus, and how influenza viruses A and B interact at the evolutionary scale. To address these questions we inferred the phylogenetic history of human influenza B virus using complete genome sequences for which the date (day) of isolation was available. By comparing the phylogenetic patterns of all eight viral segments we determined the occurrence of segment reassortment over a 30-year sampling period. An analysis of rates of nucleotide substitution and selection pressures revealed sporadic occurrences of adaptive evolution, most notably in the viral hemagglutinin and compatible with the action of antigenic drift, yet lower rates of overall and nonsynonymous nucleotide substitution compared to influenza A virus. Overall, these results led us to propose a model in which evolutionary changes within and between the antigenically distinct 'Yam88' and 'Vic87' lineages of influenza B virus are the result of changes in herd immunity, with reassortment continuously generating novel genetic variation. Additionally, we suggest that the interaction with influenza A virus may be central in shaping the evolutionary dynamics of influenza B virus, facilitating the shift of dominance between the Vic87 and the Yam88 lineages.