DNA homologies between strains of herpes simplex virus.

Twelve strains of herpes simplex virus from various geographical areas and different sites of isolation were compared by nucleic and hybridization. Within each serological type there was no detectable difference between strains gauged by the extent of the nucleic acid homology and the thermal stability of the hybrid molecules. Based on these results there is less than 5% nucleotide sequence variation within each serological type and less than 20% true homology between the two types.