VARIABILITY OCCURS IN THE INVERTED REPEAT REGION OF GENOMIC DNA FROM BOVINE HERPESVIRUS-1 RESPIRATORY, GENITAL AND BOVINE HERPESVIRUS 5 ENCEPHALITIC ISOLATES

Restriction fragment length polymorphisms (RFLPs) were detected within BHV1.1, BHV1.2, and BHV5 genomes using the restriction enzyme PstI. T he genomic areas of these changes has not been previously reported. Us ing Southern blot hybridization with DNA probes representing the entir e genome of BHV1.1, areas of genomic variation were located for a resp iratory isolate (BHV1.1), four vaccine isolates (BHV1.1), a genital is olate (BHV1.2), and two encephalitic isolates (BHV5). The most frequen tly observed RFLPs of BHV1.1 and BHV1.2 occurred within the internal r epeat region and the left terminus of the unique long region. When two separate isolates of the encephalitic BHV5 were compared, RFLPs were detected in the internal and right terminal repeat regions. These are the regions of each genome from which immediate early genes are transc ribed. No genomic variation was observed throughout the unique long an d unique short regions for all BHV1 and 5 isolates examined.