An analysis of molecular phylogeny was undertaken to examine whether the evolution of the hepadnavirus family is host-dependent. Using the nucleotide sequences of 18 strains, we constructed phylogenetic trees. The trees obtained show that all 12 strains of hepatitis B virus can be classified into four subgroups that are not compatible with conventional subtypes. We estimated the rate of synonymous (silent) substitution for hepatitis B virus to be 4.57 x 10(-5) per site per year. Applying this rate to the phylogenetic tree, we estimated that duck hepatitis B virus diverged from a common ancestor about 30,000 years ago at the earliest, that woodchuck hepatitis virus and ground squirrel hepatitis virus diverged about 10,000 years ago, and that hepatitis B virus diverged within the last 3000 years. Because these divergence times of the viruses are much more recent than those of the host species, it suggests that the hepadnavirus family evolved independently of host-species divergence.
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机译：进行了分子系统发育分析，以检查嗜肝DNA病毒家族的进化是否依赖宿主。使用18个菌株的核苷酸序列，我们构建了系统发育树。获得的树木表明，所有12种乙型肝炎病毒株都可以分为与常规亚型不兼容的四个亚组。我们估计每年每个站点的乙肝病毒同义（沉默）替换率是4.57 x 10（-5）。将这一比率应用于系统发育树，我们估计鸭乙型肝炎病毒最早是在大约30,000年前与共同祖先分叉的，土拨鼠肝炎病毒和地松鼠肝炎病毒大约在10,000年前分叉了，而乙型肝炎病毒在最近3000年。由于这些病毒的发散时间比宿主物种的发散时间要晚得多，因此表明嗜肝DNA病毒家族的进化独立于宿主物种的发散。
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