Abstract
The genome of human cytomegalovirus (HCMV) consists of 2 unique sequences, L and S, bounded by 2 sets of redundant sequences. In this arrangement, the terminal sequences (TRl and TRs) are repeated in an internal inverted form (IRl and IRs) and delimit L and S. After restriction endonuclease cleavage of the DNA, four 0.5 M and four 0.25 M fragments are found, indicating that HCMV DNA preparations consist of four equimolar populations differing only in the relative orientation of the L and S components. Cleavage of the CMV DNA with the restriction endonucleases BglII, HindIII and XbaI results in 32, 27 and 21 fragments, respectively. The arrangement of these fragments was determined using molecular hybridization techniques, identification of terminal fragments and the identification of linkage groups by double-digestion. The physical maps for the restriction endonucleases BglII, HindII and XbaI are presented.