DNA sequence of frog adenovirus

The genome of frog adenovirus (FrAdV-1) was sequenced and found to be the smallest of all known adenovirus genomes. The sequence obtained was 26 163 bp in size and contains a substantial direct repeat near the right terminus, implying that it was derived by recombination from a parental genome of only 25 517 bp. The closest relative of FrAdV-1 proved to be turkey adenovirus 3, an avian adenovirus with no previously known near relative. Sequence comparisons showed that the two viruses have equivalent gene complements, including one gene the product of which is related to sialidases. Phylogenetic analyses supported the establishment of a fourth adenovirus genus containing these two viruses, in addition to the established genera Mastadenovirus and Aviadenovirus and the proposed genus Atadenovirus. Sixteen genes were identified as being conserved between these four lineages and were presumably inherited from an ancestral adenovirus.