Abstract
An EM examination of pseudorabies virus DNA single strands after self-annealing shows a loop of single-stranded DNA at 1 end of the molecule contiguous to a double-strand region. The molecule then terminates in a further single-stranded region that does not form a loop. The DNA probably contains a sequence of 13.3 .times. 106 daltons at 1 end, which is repeated internally with opposite polarity. The segment of the genome separating the repeats has a double-strand MW of 5.4 .times. 106. The whole native DNA has a MW of 90 .times. 106-95 .times. 106.