Comparison of the genomes of pseudorabies (Aujeszky's disease) virus strains by restriction endonuclease analysis.

The DNA of pseudorabies virus (PRV) strains from the United States and Taiwan and attenuated vaccine strains from Romania were compared by restriction endonuclease analysis. Electrophoretically separated PRV DNA fragments of KpnI and BamHI digests demonstrated cleavage pattern variations which clearly distinguished the 3 Taiwan isolates from all other strains, as well as from each other. One type of variation involved the loss or gain of restriction endonuclease cleavage sites. Examples of this type of variation were clearly observed in fragment patterns of the Taiwan isolates. Another type of variation that occurred at higher frequency for fragments mapping in the repeat and repeat-unique joint regions of the PRV genome involved sequence additions or deletions from existing fragments. This second type of variation occurred in most of the strains analyzed.