Figure 1: Genome maps of Towne-varS, Towne-varL, and BAC-cloned viruses. Inverted repeats and (grey boxes) flank unique long (UL) and unique short (US) regions to delineate long and short genome segments. One or more copies of the a sequence (black bars) can be found at long segment termini and inverted at the long and short segment junction (), while one or no copies are found at short segment termini [9, 10] (for simplicity single copies are shown). Dashed lines indicate UL sequences in varL that are missing from varS; black boxes represent the BAC ori cassette (BAC). Nucleotide positions are indicated; genome features are approximately to scale.