| Objective:To undertake the genotype, serotype, gene mutation and evaluate recombinants of the hepatitis B virus (HBV) in Tibet (China).Methods:ELISA was used to check the HBV markers in serum, Nested polymerase chain reactions were used to amplify the whole sequence of HBV. SeqMan of DNAstar software was used to amplify the fragments sequenced by corporation, MEGA5 was used to create phylogenetic trees, and BioEdit was used to make sequence alignment and to undertake the gene mutation, while SimPlot software was used to make recombination analyses.Results:Twelve complete sequences of the HBV of Tibetan nationality were collected using these methods, it showed that all 12 strains were C/D recombinants. Nine recombination sites(TibetShannan-4> TibetAli-1?TibetAli-2?TibetAli-3?TibetAli-4?TibetAli-5?TibetLasa-1? TibetLinzhi-1?TibetLinzhi-2) of the 12 were at nt750, and the other three were at nt1526. Therefore, the 12 strains could be divided into two types of recombinants:C/Da and C/Db. Phylogenetic analyses of the complete sequence revealed that the 12 strains belonged to genotype C, and the nucleotide distance was >4% between the 12 strains and sub-genotypes C1 to C15 in Genbank. The most likely sub-genotype was C1. Besides, no G1896A mutations in pre-C gene occurred in the 12 strains, while A1762T and G1764A double mutations occurred in 2 strains (TibetLasa-1 and TibetShannan-4). The 126th amino acid of all 12 strains in S gene were GGG except TibetShannan-1?TibetShannan-2 and TibetShannan-3 which were GAG instead. The 145th amino acid of all 12 strains were all TTC. 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. This study 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. |
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