Genome
The genome is a linear duplex DNA molecule, a laboratory strain has 124,884 base pairs. The genome has 2 predominant isomers, depending on the orientation of the S segment, P (prototype) and IS (inverted S) which are present with equal frequency for a total frequency of 90-95%. The L segment can also be inverted resulting in a total of four linear isomers (IL and ILS). This is distinct from HSV's equiprobable distribution, and the discriminatory mechanism is not known. A small percentage of isolated molecules are circular genomes, about which little is known. (It is known that HSV circularizes on infection.)
Read more about this topic: Varicella Zoster Virus