Analysis of genetic variability of populations of herpes simplex viruses.

An analysis of genetic variability of herpes simplex virus type 1 and type 2 populations of the Madrid (Spain) area has been carried out by digestion of viral DNA with restriction endonucleases. The index of nucleotide diversity indicated that herpes simplex virus type 1 has a slightly, although statistically significant, higher degree of heterogeneity than type 2. A phylogenetic tree for each type of virus has been constructed. The evolutionary pattern followed by both types of viruses ('star-like' topology) suggest that all the isolates analyzed evolved from a unique origin for each type of virus.