The linkage map characteristic of Escherichia coli. In preparation for genetic transfer during conjugation, the ring-shaped chromosome of an Hfr bacterium breaks in such a way that when the ring opens the F factor is left attached to the region of the chromosome destined to enter the F− cell last. Circular linkage maps have been constructed for several other bacteria and for certain viruses. See also linkage map.
Subjects: Genetics and Genomics.