Analysis of two genomic variants of orang-utan hepadnavirus and their relationship to other primate hepatitis B-like viruses

We recently described orang-utan hepadnavirus (OuHV) (Warren et al., Journa l of Virology, 73, 7860-7865, -1999). Phylogenetic analyses indicated that the various isolates of OuHV can be divided into two genomic variants. Two representatives from each genomic cluster were analysed both molecularly an d phylogenetically. Their genome organization was highly similar to other h epadnaviruses of apes and humans. The complete genome sequences of the two OuHV types had an overall 5% sequence difference. Research on 25 seropositi ve Bornean orang-utans showed that, of the 19 animals infected with one var iant, 12 originated from East Kalimantan. Phylogenetic analysis was perform ed using the full-length genomes of various primate hepadnaviruses. The tre e topology revealed one cluster of Old World hepadnaviruses that is divided into two subclusters, one consisting of the ape viruses, and the other com prising the human genotypes A-E. These data suggest that the great apes and gibbons have been infected with a common ancestor hepadnavirus.