METHODOLOGY R o p

hepatitis B virus (HBV) genotypes show not only geo-graphical distribution and race specificity, but also are associated with disease progression and response to interferon treatment [1,2]. According to sequence divergence of greater than 8% over the entire genome, or greater than 4 % for the S gene, HBV has been classified into eight different genotypes A-H [3-6]. Different subgenotypes for each genotype have also been identified and defined by sequence divergence of between 4 % and 8 % of the full genome [7]. Hepatitis B is endemic in China, with a hepatitis B sur-face antigen (HBsAg) carrier rate of 7.18 % [8]. HBV mo-lecular epidemiological studies showed that genotypes B and C were predominant in China. Genotype A (few and scattered), D (predominant in Uyghur patients of Xinjiang) and C/D recombinant (mainly found in Tibet) were also detected in China [9,10]. The predominan