Variation in the HindIII Restriction Fragments of DNA from the Chinese Tian Tan Strain of Vaccinia Virus

HindIII fragments D to P of DNA from a Chinese vaccine strain (Tian Tan) of vaccinia virus have been molecularly cloned into the plasmid pAT153 at the unique HindIII site. The Chinese strain DNA differs from a non-vaccine American strain (WR) in having an additional HindIII fragment (P). Twelve HindIII D clones and 12 HindIII F clones of the Chinese strain were analysed by digestion by EcoRI, BamHI, PstI and XhoI. Two forms of D (designated a and b) and of F (a and b) were demonstrated. In each the differences were detected as the presence of an additional EcoRI site, in Da and Fa. The HindIII Fa and Fb fragments of the Chinese strain were shown to differ significantly from the WR strain in their restriction site maps.