Whole genome analysis of a novel adenovirus discovered from Oriolus chinesis

We present the first complete genome sequence of an aviadenovirus Oriolus adenovirus (OrAdV) sequenced from the cloaca of a Oriolus chinensis (a passerine bird widely distributed in Asia), which was collected from an island off the east coast of China. Thirty-one protein coding genes were predicted in this 40425-bp-long genome. OrAdV genome is highly divergent and has only 57% average protein identity compared with other aviadenovirus genomes. Comparative genomic analysis indicates that this passerine virus is a new species of aviadenovirus. One unique thymidylate kinase gene was discovered in OrAdV genome. This gene is absent in other adenovirus genomes and usually reported to occur in herpesvirus. Protein sequence alignment against all known proteins indicates that this gene may be originated from ancient horizontal gene transfer event between virus and parasitic eukaryote like protozoan. This new aviadenovirus genome enriches the genomic information of adenovirus and suggests that there is a large unknown space of adenovirus world.