Hfr: a strain with F integrated into the chromosome that will give efficient transfer of some chromosomal markers F* plasmid: 1) Transfers itself at a frequency of 0. 1 2Does not transfer chromosomal markers 1) Transfers some chromosomal markers efficiently 2)Other markers transferred inefficiently -Gradient of transfer (It takes about 100 minutes to transfer the entire chromosome) Consider an F* integrating to make an hfr A A This process can be reversed to go back to the F+ state F he recombination can occur at a different position to give an F plasmid that carries a part of the chromosome. This form of F is called an F MB c B CHfr: a strain with F integrated into the chromosome that will give efficient transfer of some chromosomal markers. F+ plasmid: 1) Transfers itself at a frequency of 0.1 2) Does not transfer chromosomal markers Hfr 1) Transfers some chromosomal markers efficiently 2) Other markers transferred inefficiently - Gradient of transfer (It takes about 100 minutes to transfer the entire chromosome) Consider an F+ integrating to make an Hfr: A B C D B C D A This process can be reversed to go back to the F+ state: A B C D F+ The recombination can occur at a different position to give an F plasmid that carries a part of the chromosome. This form of F is called an F’. B C D B C A