Case III: Sexduction or F-duction: Conjugation between F’ cell and F- cell
What is F’ cell?
F’ cell: The integration of F plasmid in the formation of Hfr strains is reversible process. At times, detached F factor contains one or more bacterial genes that were close to the integrated F factor. Such a cell is referred as F’ (F dash cell)
F’ cell has an independent detached F plasmid with some bacterial genes attached to it. Then plasmid is called F’ plasmid.
Sexduction: is the conjugation between F’ cell with F- recipients. Sexduction offers high rate of recombination. After conjugation, F- cell receive f plasmid along with few bacterial genes. Thus F- cell becomes diploid for few genes (partial diploids).
Step 1: Formation of F’ cells or F’ plasmids
Step 1: F plasmid detaches from the parent chromosome. During this release, genes that are close to integrated F plasmid may attach to the detached F plasmid. Such a cell that has a detached F plasmid with some bacterial genes attached to it is referred as F’ cells
Step 2: F’ cells produces hair like appendages called sex pili which facilitates cell to cell contact with F- strain by forming a conjugation tube. The formation of sex pili is governed by genes of F factor
Step 3: Replication of F’ plasmid making a copy
Step 4: Transfer of copy of F’ plasmid to the recipient cell via conjugation tube.
Step 5: Conjugation tube dissolves. Now F- cell is diploid for few bacterial genes (or partial diploid).
Step 6: The transferred F’ plasmid has some bacterial genes attached to it. This brings about genetic variability.
In short: F’ cell + F- cell = F’ cell + F’ cell
To conclude, bacterial gene transfer is not like sexual reproduction in higher organisms. Only a few genes or F plasmid is transferred from donor bacterium to recipient bacterium in the process.