Construction of recombinant viruses. Solid lines represent wild-type HCMV genomic DNA, dotted lines represent G2 HCMV DNA, and bold line segments represent either wild-type or G2 HCMV DNA. (A1) AD169-BAC with either genes UL13-46 or UL46-68 replaced with the Zeocin resistance cassette. (A2) G2 HCMV cosmids. (A3) Recombinant viruses in which the Zeocin resistance cassette was replaced with either UL13-46 or UL46-68 genes from G2 HCMV. (B) Recombinant viruses in which genes UL13 to UL35, UL20 to UL46, UL26 to UL46, or UL32 to UL46 were from G2 HCMV. Details on construction of these viruses are provided in Materials and Methods.