GENETIC DIVERSITY OF HEPATITIS-B VIRUS-STRAINS ISOLATED IN RIO-DE-JANEIRO, BRAZIL

Hepatitis B virus (HBV) genomes have been classified into six groups, A-F, group F being the most divergent. South America has provided the smallest number of strains studied at the genome level. The only HBV s train from this region sequenced completely has been classified in gro up F, and contains the most divergent of the HBV genomes presently kno wn [Naumann et al. (1983): Journal of General Virology 74:1627-1632]. To evaluate genetic relatedness between strains isolated in South Amer ica and in the rest of the world, a restriction endonuclease analysis was carried out on 14 HBV strains (4 adw2, 3 adw4, 3 ayw2, and 4 ayw3) isolated in Rio de Janeiro, Brazil. C, pre-S, and X genes along with the 5' part of the P gene from these strains were amplified by the pol ymerase chain reaction. The DNA fragments were digested by BamHI, BstE II, EcoRI, HhaI, and TaqI endonucleases. The restriction patterns obta ined were compared with those deduced from the nucleotide sequence of 26 HBV strains isolated in other continents. The results showed a larg e genetic variability of Brazilian strains. Taking into account that a ll the samples examined possessed the w antigenic subdeterminant, the number of different restriction patterns of strains isolated in Rio de Janeiro was at least as large as that of the reference strains isolat ed in the rest of the world. Some original restriction patterns were f ound in adw4 and ayw2 HBV strains. (C) 1994 Wiley-Liss, Inc.