Sequence analysis of pre-S/S gene of hepatitis B virus strains of genotypes A, D, and F isolated in Brazil.

The nucleotide sequences of pre-S/S gene of nine hepatitis B virus strains (3 adw2, 3 ayw2, and 3 ayw 3) and of pre-S region of two adw4 isolates from Rio de Janeiro, Brazil, were determined. Phylogenetic analysis allowed to classify these strains into three genotypes, A, D and F, reflecting the diverse origin of the population. However, strains belonging to a same genotype were separated by a short evolutionary distance. The presence of aminoacid mutations into Pre-S region not found in hepatitis B viruses isolated in other parts of the world is described.