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

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 C15 in 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.