SEQUENCE-ANALYSIS OF PRE-S S GENE OF HEPATITIS-B VIRUS-STRAINS OF GENOTYPE-A, GENOTYPE-D, AND GENOTYPE-F ISOLATED IN BRAZIL/

The nucleotide sequences of pre-S/S gene of nine hepatitis B virus str ains (3 adw2, 3 ayw2, and 3 ayw3) and of pre-S region of two adw4 isol ates from Rio de Janeiro, Brazil, were determined. Phylogenetic analys is allowed to classify these strains into three genotypes, A, D and F, reflecting the diverse origin of the population. However, strains bel onging to a same genotype were separated by a short evolutionary dista nce. The presence of aminoacid mutations into pre-S region not found i n hepatitis B viruses isolated in other parts of the world is describe d.