An analysis of the molecular evolution of Hepatitis B viral genotypes A/B/D using a Bayesian evolutionary method

BACKGROUND: Hepatitis B virus (HBV) infection is a major global health problem. The infectious virion contains an inner “core particle”, which is made of 180 or 240 copies of core protein, alternatively known as hepatitis B core antigen, or HBcAg which encloses the viral genome. METHOD: In this study, we characterized HBV genotypes and used Bayesian analyses to estimate date of emergence of the most recent common ancestor (TMRCA) of three HBV genotypes, A, B, and D. RESULTS: We estimated that the rate of evolution of HBV core protein gene to be 1.127 (0.925–1.329, 95% HPD) substitutions per site per year. The TMRCA of HBV for genotypes A, B, D were 118 (54–194, 95% HPD) year, 184 (78–323, 95% HPD) year and 133 (65–230, 95% HPD) year, respectively. Demographic histories of the HBcAg gene showed that the relative genetic diversity had a sharp increase within the first 10 years of its emergence. CONCLUSION: Using a bayesian evolutionary method to predict the outbreak trends of HBV through evolutionary trees of HBV, and provide theoretical foundations for clinical prevention and treatment of HBV.