Abstract
The multigenic kps cluster in Escherichia coli K1 encodes functions for synthesis of a polysialic acid capsule. DNA probes flanking each side of the cluster were hybridized to lambda clones bearing overlapping E. coli W3110 genomic fragments. These fragments covered the region between 60 and 70 map units on the chromosome. The results located kps to an accretion domain near 64 map units and established the orientation of kps cluster genes. Acquisition of kps by the E. coli genome was apparently the result of an ancestral transpositionlike addition event.