(A to D) Agarose gel electrophoresis and Southern hybridization of phage DNAs. (A) Agarose gel electrophoresis of restriction endonuclease-digested DNA of phages 6220, H-19B, and 933W. Lane 1, molecular mass marker (bacteriophage λEco130I; MBI Fermentas); lane 2, EcoRI-digested DNA of phage 6220; lane 3, EcoRI-digested DNA of phage H-19B; lane 4, PvuII-digested DNA of phage 933W. (B) Hybridization of gel shown in panel A with EcoRI-digested DNA of phage 6220 as the gene probe. (C) Hybridization of gel shown in panel A with EcoRI-digested DNA of phage H-19B as the gene probe. (D) Hybridization of gel shown in panel A with PvuII-digested DNA of phage 933 as the gene probe.