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Updated: Aug 15, 2026

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes
Published on: July 27, 2018
Comparative analysis of genome sequences of three isolates of Orf virus reveals unexpected sequence variation
Andrew A Mercer1, Norihito Ueda, Sonja-Maria Friederichs
1Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin, New Zealand. andy.mercer@stonebow.otago.ac.nz
Abstract:
Orf virus (ORFV) is the type species of the Parapoxvirus genus. Here, we present the genomic sequence of the most well studied ORFV isolate, strain NZ2. The NZ2 genome is 138 kbp and contains 132 putative genes, 88 of which are present in all analyzed chordopoxviruses. Comparison of the NZ2 genome with the genomes of 2 other fully sequenced isolates of ORFV revealed that all 3 genomes carry each of the 132 genes, but there are substantial sequence variations between isolates in a significant number of genes, including 9 with inter-isolate amino acid sequence identity of only 38-79%. Each genome has an average of 64% G+C but each has a distinctive pattern of substantial deviation from the average within particular regions of the genome. The same pattern of variation was also seen in the genome of another parapoxvirus species and was clearly unlike the uniform patterns of G+C content seen in all other genera of chordopoxviruses. The availability of genomic sequences of three orf virus isolates allowed us to more accurately assess likely coding regions and thereby revise published data for 24 genes and to predict two previously unrecognized genes.
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