Southern blot analysis of KOS, KOSV2, KOSvhsBG, and KOSV2R, using pUL41 as a probe. Positions of the fragments with the expected sizes resulting from a BamHI digestion are indicated on the right: 6.6- and 3.9-kb fragments for KOS and KOSV2R (lanes 2 and 5, respectively), 10.5-kb fragments for KOSV2 (lane 3), and 6.9-, 3.9-, 3.0-, and 1.0-kb fragments for KOSvhsBG (lane 4). Sizes of BstEII digested bacteriophage lambda are indicated on the left in kilobases.