FIG. 1.

(A) Restriction-digested asccφ28 DNA electrophoresed on a 1% agarose gel and stained with ethidium bromide. (B) Southern hybridization of the same fragments probed with DNA from phage P369. The lanes contained the following: lane 1, uncut DNA; lane 2, HindIII restriction enzyme digest; lane 3, AccI restriction enzyme digest; lane 4, ScaI restriction enzyme digest; lane 5, SpeI restriction enzyme digest; lane 6, AatII restriction enzyme digest; lane 7, marker coliphage λ DNA cut with PstI. DNA bands not obvious in the ethidium bromide-stained gel are visible in the Southern hybridization and presumably represent incomplete digestion products. Selected sizes of the marker are indicated between the panels.