基于全基因组序列对新型H7N9禽流感病毒进化率评估  

Evolutionary rate of novel influenza A H7N9 virus based on full-length sequences

作　　者：黄萍[1] 王美霞[2] 袁满琼 HUANG Ping, WANG Mei-xia, YUAN Man-qiong(Qilu Hospital of Shandong University, Ji＇nan, Shandong Province 250012, Chin)

机构地区：[1]山东大学齐鲁医院,山东济南250012 [2]厦门大学公共卫生学院

出　　处：《中国公共卫生》2018年第3期396-400,共5页Chinese Journal of Public Health

基　　金：国家自然科学基金(81402768);山东省重点研发计划项目(2015GSF118148)

摘　　要：目的基于新型H7N9禽流感病毒的全基因组序列,估算该病毒8个基因结构区及整体的进化率,为进一步探索H7N9的进化机制提供理论支持。方法选取全球共享禽流感数据倡议组织(GISAID)中以人类为宿主的H7N9病毒基因序列,同时合并与新型H7N9的6个内部基因结构区具有高度同源性的H9N2序列;采用Bio Edit7.0软件进行多序列比对,MEGA 6.06建立系统发育树;利用Path-o-gen软件初步估算进化率,并以此作为先验信息,基于分子时钟和蒙特卡罗马尔科夫链(MCMC)模型进一步估算H7N9各基因结构区的进化率。结果进化率结果表明H7N9禽流感病毒进化快,全基因进化率为4.60×10^(–3)次/位点/年(95%CI=3.94×10^(–3)~5.40×10^(–3)),血凝素(HA)和神经氨酸酶(NA)具有较快的进化率,分别为7.43×10^(–3)和5.92×10^(–3)次/位点/年,聚合酶A(PA)、聚合酶B1(PB1)和聚合酶B2(PB2)进化速度也相对较其他基因片段快。结论 H7N9病毒进化速度快,急需建立一个有效长期的流感病毒监测制度。Objective To assess the evolutionary rate of novel influenza A H7N9 virus based on the full length sequences and to provide a theoretical guidance for making prevention and control strategies.Methods The sequences of the influenza A H7N9 virus from The Global Initiative on Sharing Avian Influenza Data （GISAID） were used to construct phylogenetic trees using programs BioEdit 7.0 and MEGA 6.06. Preliminary evolutionary rates were estimated with Path-o-gen; then using the preliminary rates as prior information, we further estimated the rates with BEAST 1.8.2 based on molecular clock and Monte Carlo Markov Chain （MCMC） model.Results High evolutionary rates of the novel influenza A H7N9 virus were observed. The mean evolutionary rate for full-length genomic sequences is 4.60×10-3 （95% highest probability density[HPD]：3.94×10-3, 5.40×10-3） subs/site/year. The evolutionary rate of nucleotide substitution of haemagglutinin and neuraminidase （7.43 and 5.92×10-3 subs/site/year） are higher than the evolutionary rate of the H7N9 and higher evolutionary rates of polymerase A （PA）, polymerase B1 （PB1）, and polymerase B2 （PB2） genes were also observed.Conclusion The novel influenza A H7N9 virus evolves at a high rate, suggesting that effective and long-term surveillance should be carried out.

关 键 词：H7N9 分子时钟 蒙特卡罗马尔科夫链(MCMC)模型 进化率 

分 类 号：R183[医药卫生—流行病学]