The nucleotide sequence of surface antigen gene of hepatitis B virus subtype adr

The nucleotide sequence of the XhoI-BamHI fragment (1279bp), which contains the surface antigen gene (S gene) of HBVadr, was determined by Maxam and Gilbert's method. By comparing the differences both of the nucleotide sequence in the S gene and its coded amino acid sequence between adr and those reported for adw, ayw and adyw, some new variation sites were discovered. The differences were mainly distributed in the two hydrophilic regions. However, at those sites which might show biological function, there were no variations among different subtypes, they are relatively conservative in heredity and evolution. Comparing the variation of the nucleotide sequence in the S gene region with that in the non-S gene region, it is shown that the frequency of variation in the non-S gene region doubled that in the S gene region. The S gene region is more conservative.