Comparative genetic analysis of genomic DNA sequences of two human isolates of Tanapox virus

Members of the genus Yatapoxvirus, which include Tanapox virus (TPV) and Yaba monkey tumor virus, infect primates including humans. Two strains of TPV isolated 50 years apart from patients infected from the equatorial region of Africa have been sequenced. The original isolate from a human case in the Tana River Valley, Kenya, in 1957 (TPV-Kenya) and an isolate from an infected traveler in the Republic of Congo in 2004 (TPV-RoC). Although isolated 50 years apart the genomes were highly conserved. The genomes differed at only 35 of 144,565 nucleotide positions (99.98% identical). We predict that TPV-RoC encodes 155 ORFs, however a single transversion (at nucleotide 10241) in TPV-Kenya resulted in the coding capacity for two predicted ORFs (11.1L and 11.2L) in comparison to a single ORF (11L) in TPV-RoC. The genomes of TPV are A + T rich (73%) and 96% of the sequence encodes predicted ORFs. Comparative genomic analysis identified several features shared with other chordopoxviruses. A conserved sequence within the terminal inverted repeat region that is also present in the other members of the Yatapoxviruses as well as members of the Capripoxviruses, Swinepox virus and an unclassified Deerpox virus suggests the existence of a conserved near-terminal sequence secondary structure. Two previously unidentified gene families were annotated that are represented by ORF TPV28L, which matched homologues in certain other chordopoxviruses, and TPV42.5L, which is highly conserved among currently reported chordopoxvirus sequences.