2 MAJOR DNA VARIANTS PRESENT IN SERIALLY PROPAGATED STOCKS OF THE WR-STRAIN OF VACCINIA VIRUS

Two major DNA variants have been isolated from serially propagated stocks of the WR strain of vaccinia virus. Restriction enzyme mapping of the 2 variants with HindIII, AvaI, XhoI, SstII and SmaI revealed a 6.3 megadalton (Md) deletion in the smaller DNA variant. The deletion was mapped at .apprx. 6.8 md in from the left terminus, just beyond the inverted terminal repeat. The additional DNA present in the larger variant represented unique viral sequences that were transcribed in vitro and in vivo. One-step growth curves in HeLa (human cervical cancer) cells revealed no difference in rate of replication or burst size when progeny were scored on CV-1 (African green monkey kidney cell) monolayers.