Location of the gene specifying hexose phosphate transport (uhp) on the chromosome of Escherichia coli.

The uhp gene, which specifies the uptake of hexose phosphates, and several other genes in the vicinity of minute 81 on the E. coli linkage map have been located by phage-mediated transductions. The order found is mtl-gpsA-pyre-gltc-uhp-tna-dnaa. Alleles specifying the Uhp- and Uhp+ characters were separated from that specifying constitutivity of hexose phosphate uptake (Uhpc). Although cotransduction frequencies between gltC and uhp as high as 90%, and between uhp and tna as high as 80%, were observed, these frequencies were unusually strongly dependent on which marker was selected. This may be due to the proximity of the uhp region to the point of origin of chromosome replication.