Map of DNA homology between the genomes of Salmonella bacteriophages P22 and L.

The genomes of temperate Salmonella typhimurium phages P22 and L share approximately 69% homology, as measured by DNA heteroduplex analysis. Alignment of the P22/L heteroduplex molecules with a P22 physical map places most of this homology between the capsid genes and genes in the vicinity of the prophage attachment sites. The degree of genetic relatedness between these phages and the lambdoid phages is also discussed.