Sexduction or F-duction - Conjugation between F’ cell and F- cell

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).

Sexduction or F- duction: Transfer of F factors to receipt occur in mating between F¹ and F^- . The transfer of F¹ to receipient produce partial diploids or heterogenotes. Recombination may occur between the recipient’s chromosome and F1, producing recombinants. Recombination of this type, mediated by F¹ factors, is called sexduction or F-duction. (Here a, b and c are representative genes)

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.