Abstract
Human cytomegalovirus DNA was isolated from infected cells by the Hirt method (B. Hirt, J. Mol. Biol. 26:365-369, 1967). The restriction endonuclease cleavage patterns of DNA obtained in this manner were comparable with those of DNA extracted from purified virions. The "Hirt supernatants" were satisfactory for identifying individual cytomegalovirus strains by their DNA fingerprinting.