Differences between F and HFr plasmid

F-Plasmid:

1. F-plasmid is fertility factor, it contains the genes require for the transfer or conjugation.
2. F(+) * F(-) ……… recipient becomes F(+).
3. Low rate of recombination .
4. It takes 2 minutes for the transfer of F-plasmid.
5. One strand of the F factor is nicked and moves across the conjugation tube. The DNA complement is synthesized on both strands. The entire F-plasmid factor moves in the recipient cell.
6. The transferred F-factor synthesizes its DNA complement and get circularize independently in the recipient cell. 

HFr-Plasmid:

1. HFr-plasmid is a special case of F(+) cells. i.e., a cell with an integrated F.
2. HFr * F(-) ……… recipient becomes F(-).
3. High rate of recombination .
4. It takes 100 minutes for an entire chromosome to be transferred.
5. During transfer of Hfr DNA to a recipient cell, the mating pair usually breaks apart before the entire chromosome is transferred.
6. In Hfr transfer, the transferred DNA fragment does not circularize and cannot replicate but one or more of its regions is frequently exchanged with the chromosome of the recipient, thereby generating recombinants in the F(-) cells.