Mapping loci for surface exclusion and incompatibility on the F factor of Escherichia coli K-12.

A series of Hfr deletion strains carrying deletions extending different distances into the integrated F factor have been used to map loci for surface exclusion (traS) and for incompatibility (inc) on the Escherichia coli K-12 sex factor F. traS mapped between traG and traD. It forms a part of the large operon, including all the known transfer genes except traJ, and is co-controlled with these. The product of traS is not required for formation of the F pilus. inc mapped between the phi(R) (11) locus and the origin of transfer; it is therefore one of the earliest loci transferred during conjugation.