Phylogeny of Duck Enteritis Virus: Evolutionary Relationship in the Family Herpesviridae

OBJECTIVE: To understand the evolutionary relationship of duck enteritis virus (DEV) in the family Herpesviridae and the genome organization of DEV. METHODS: A modified 'targeted gene walking PCR' method was used to amplify the unknown gene of DEV Clone-03 strain adjacent to a short stretch of known sequence. The assembled unknown fragment was confirmed to be a homologue of herpesviruses by BLAST analysis and comparison with other herpesviruses homologues. Open reading frames (ORFs) were determined and analyzed by Gene Runner software and an online transcriptional element search engine. Two evolutionary analysis approaches were used to conduct phylogenetic trees of DEV in relation to herpesviruses based on the deduced amino acid sequences. RESULTS: A genomic fragment encompassing 25,625 nt and containing 16 ORFs was amplified, determined, and compared with homologues in other herpesviruses. Phylogenetic trees indicated that DEV and other herpesviruses generated from one ancestor and DEV were grouped into the subfamily Alphaherpesvirinae. In most cases, DEV showed a close relationship with the genus Mardivirus, but formed a single branch. CONCLUSION: Partial genomic organization and phylogenetic analysis in the present study provides evidence that DEV was a member of the subfamily Alphaherpesvirinae and should be assigned as a single group.