Fig. 1

A midpoint rooted tree showing the relationship between the Vietnamese HBV genome sequences with 70 reference sequences (all genotypes and subgenotypes). Tree was constructed using RAxML v7.2.8 available in Geneious software using GTR + G + I nucleotide substitution model with 100 bootstrapping replicates. Bootstrap values greater than 70% are shown on the branch nodes. The Vietnamese HBV strains are presented as VN HBV followed by isolate number and reference genomes are presented as subgenotype followed by Gene Bank accession number. The reference genomes (B2, B4 and C1) are highlighted with a filled dark circle. Reference genomes with multiple sequences for each genotype and subgenotypes (genotype and subgenotype A, D, F, I and subgenotype C6, C8 and C13) were clustered. The scale bar indicates the number of nucleotide substitution. Genotype, subgenotype and Gene Bank accession number of reference sequences are listed in Additional file 3