FIG. 6.

Southern blot of phage SM1 genomic DNA and SF100 chromosomal DNA. Lanes 1, 3, and 5 contain phage DNA. Lanes 2, 4, and 6 contain chromosomal DNA. DNA was digested with EcoRI, and membranes were hybridized with probes corresponding to pblA (lanes 1 and 2), pblB (lanes 3 and 4), or pblT (lanes 5 and 6). One of two pblB fragments is a different size in the phage DNA (lane 3) than in the SF100 chromosomal DNA (lane 4), which indicates the presence of an attachment site within these fragments.