COMPARATIVE GENOME MAPPING WITH MOBILE PHYSICAL MAP LANDMARKS

We describe a method for comparative macrorestriction mapping of the c hromosomes of Escherichia coil strains. In this method, a series of ph ysically tagged E. coli K-12 alleles serve as mobile landmarks for map ping DNAs from other strains. This technique revealed evidence of stra in-specific chromosomal additions or deletions in a pathogenic isolate and can be applied to most strains, yielding information on genealogy as well as virulence. In theory, the same strategy can be used to map and compare genomic DNAs from a wide variety of species.