Herpes simplex virus type 1 restriction fragment polymorphism determined using southern hybridization.

Regions of herpes simplex virus type 1 (HSV-1) DNA with variation in the size of restriction endonuclease fragments were identified by comparison of the BamHI, KpnI or SalI restriction endonuclease digestion patterns among 15 HSV-1 isolates after hybridization with specific 32P-labeled cloned HSV-1 DNA fragments. Of the types of restriction fragment polymorphism identified, one was a strain with a distinctly different restriction fragment than the prototype (loss or gain of restriction sites). Another type, the specific fragment varied only in size among strains. Thirteen distinct variations were identified. Ten were mapped to the unique sequence of the L component; two to the inverted repeat of the L component and one to the inverted repeat of the S component. The presence of a common ancestor from which some isolates of HSV-1 might derive was deduced from an analysis of the distribution of the thirteen variations among the 15 HSV-1 isolates.