a型禽流感病毒分子模式分析word格式论文.docx

对两株新分离 H5N1 亚型禽流感毒株进行了基因组序列分析，并采用跨宿主传播表型相关联的模式分类方法，对两株病毒进行了预测。结果显示，两株病毒为 N 类群， 不具备感染人的能力。对两株病毒的分析，是分子模式研究的应用。关键词： A 型禽流感病毒， 基因组， 小波包， 层次聚类， H5N1 亚型AbstractH5N1 viruses were continuously reported to be epidemic from 2003 and caused serious economic loss, to which much social attention has been paid. Avian influenza A viruses could directly infect humans and other mammals. Although avian influenza viruses could not spread among humans, they had partly adapted humans and mammals and could deduce pandemics. The differences between the sequences of avian influenza viruses are valuable to be studied. The molecular characterizations of avian influenza viruses isolated from humans are very important.In this research, the genome sequences of 239 influenza A viruses with different subtypes were transformed and classified to find the patterns associated with the phenotype of interspecies transmission. The energy features were extracted by the method of wavelet packet decomposition and used for virus classification by the method of hierarchical clustering. The clustering results showed that five patterns exist in avian influenza A viruses, which associated with the phenotype of interspecies transmission, and that avianviruses with patterns C and E （Y Cluster）could across species barrier and those withpatterns A, B and D （N Cluster）might not have the abilities.Based on the Euclidean distances，39 key sits were founded. The 39 sites are conserved within individual patterns and varied among patterns. 13 key sites located in NS1, which suggested that NS1 mutated fastest. Moreover, the low similarity sequences in natural‘gene reservoir’ were reconstructed with the method of the maximum likelihood. Except M1 and NS1, four other inner proteins had small clusters and PB2 had Y cluster for a short time. It was suggested that the interspecies transmission of avian influenza A viruses is an emergence. The reason is that the ranges of human activities expanded and the chance of the contacts