A bacterial strain that transfers chromosomal genes during conjugation?

A high-frequency recombination (Hfr) strain transfers chromosomal genes during conjugation. Hfr strains form when a conjugative plasmid, such as the F plasmid, integrates into the bacterial chromosome. During conjugation, the Hfr strain initiates DNA transfer starting at the plasmid’s origin of transfer. As the process progresses, adjacent chromosomal genes are also transferred. However, full transfer of the chromosome is rare due to the lengthy time required.