Investigators have found evidence of Hepatitis B virus (HBV) in the mummified remains of a Korean child from the 16th century (Hepatology 2012; 56: 1671-80).
There are at least 10 HBV genotypes (A-J) and several sub genotypes; each have a specific geographical distribution. Genotypes are defined by an >8% sequence divergence whereas as sub genotypes have 4-8% sequence divergence. The HBV in this study corresponds to C2 clade.
While the technical aspects are fascinating, the other important contribution of this article is to the understanding of the evolutionary history of HBV. There are two theories with regard to the origin of HBV, which may have occurred 100,000 years ago. One suggests a primate origin with subsequent cross-species transmission. Another theory suggests a common ancestor of HBV for primates and humans.
In this study, the mummy-derived HBV has the same genotype C which is currently predominant in Korea (>95%); and C2 sub genotype is the most common sub genotype.
The studies conclusions regarding the identification of the subtype is supported by the process of testing the samples in three independent laboratories. The genetic diversity noted in the sample is likely related to natural evolutionary processes.
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