Arch Virol (2001) 146: 1803–1810
Phylogenetic analysis of the hepatitis B virus (HBV)
genotype F including Argentine isolates
V. A. Mbayed, L. Barbini, J. L. López, and R. H. Campos
Cátedra de Virolog
ıa, Facultad de Farmacia y Bioqu
Universidad de Buenos Aires, Buenos Aires, Argentina
Accepted April 20, 2001
Summary. Seven human hepatitis B virus (HBV) genotypes have been described.
Genotype F, indigenoustotheAmericas, is the most diverging group. Our in-depth
analysis of the genetic distances of this genotype included ten Argentine samples.
Phylogenetic analysis on the small (S) gene of the surface antigen showed four
different clusters within genotype F, which were associated with a well-deﬁned
geographical origin. Even closely connected sequences sharing a common an-
cestor had shown some characteristics or markers indicating geographical dif-
ferentiation. Nucleotide sequences and amino acids translated according to the
polymerase open reading frame (P-ORF), rather than S-ORF, yielded a more
Hepatitis B virus (HBV) is a blood-borne hepatotropic virus, that has chronically
infected around 300 million people worldwide.
This virus is classiﬁed as part of the Hepadnaviridae family. The viral genome
is a partially double-stranded DNA molecule, whosecoding organization is highly
compact and over half of the sequence is translated in alternatively open reading
frames (ORF). The overlapping of the genes may result in a constrained evolution
of the genomic regions. Avian and mammalian representatives have been studied.
The mammalian HBV includes those viruses infecting rodents, humans and other
primates. A genetic classiﬁcation based on the comparison of complete human
HBV genomes has deﬁned six genotypes, named A to F [8, 9]. More recently,
another genotype, named G, has been described .
As for the study of human HBV origins, different researches have tried to
determinethe relationship betweenthe humangenotypes and alsotheir connection
with ape viruses [6, 11, 12]. Genotype F, indigenous to the Americas, appears as