西藏部分地区12株藏族人群C/D重组型乙型肝炎病毒全基因序列分析

Whole-sequence Analyses for 12 HBV C/D Recombinants from a Population in Tibet(China)

为了解藏族人群中流行的乙型肝炎病毒(HBV)基因型及基因重组状况,收集藏族人群HBsAg阳性样本,提取HBV DNA并用巢氏PCR的方法扩增HBV全长序列,测序后用DNAstar软件拼接全基因序列,进一步利用MEGA6和Simplot软件进行序列同源性和系统进化分析。应用该方法获得12株藏族人群HBV全基因序列,分析结果显示12株样本为C/D重组型,其中9株样本的重组位点位于nt750,3株样本的重组位点位于nt 1526,以此可分为两种重组方式,分别命名为C/Da和C/Db;从总体序列同源性来分析12株样本均属于C基因型,且与现有的C1-C15亚型的核苷酸差异均大于4%,与C1亚型最为接近。从地理分布来看,C/Da来自西藏中部和北部的拉萨市、阿里和林芝地区,C/Db均来自西藏南部的山南地区,提示两种重组型C/Da和C/Db在西藏地区的地理分布具有一定规律。研究结果可为西藏地区特殊HBV基因重组、基因特征分析、病毒进化研究以及当地乙肝防控提供参考。

We wished to undertake molecular genetic typing and evaluate recombinants of the hepatitis-B virus（HBV）in Tibet（China）.Multistage random sampling was used to collect HBsAg-positive samples.Nested polymerase chain reactions were used to amplify the whole sequence of the HBV.DNAstar,MEGA6 and SimPlot were used to assemble sequences,create phylogenetic trees,and undertake recombination analyses.Twelve whole sequences of the HBV of a Tibetan population were collected using these methods.Results showed that all 12 strains were C/D recombinants.Nine of the recombinations were at nt750,and the other three at nt1526.Therefore,the 12 strains could be divided into two types of recombinants：C/Da and C/Db.Analyses of the sequence of the whole genome revealed that the 12 strains belonged to genotype C,and that the nucleotide distance was〉4% between the 12 strains and sub-genotypes C1 to C15in Genbank.The most likely sub-genotype was C1.Individuals with C/Da were from central and northern Tibet（e.g.,Lasa,Linzhi,Ali）and those with C/Db recombinants were from Shannan in southern Tibet.These data suggest that the two types of recombinants had a good distribution in Tibet.Also,they can provide important information for studies on HBV recombination,gene features,virus evolution,as well as the control and prevention of HBV infection in Tibet.