F-Prime

F-Factor / F-Prime

F-Factor / F-Prime

The factor with its extra DNA is now called an F' factor (pronounced F-prime). It results in a recipient with its own genes for a particular process as well as additional genes from the donor for that same process. In the genetic sense, the recipient is a partially diploid organism since there are two genes for a given function

Conjugation has been demonstrated among various genera of bacteria in contrast to transformation which appears to occur only among cells of the same species. For example, conjugation is known to occur between Gram negative Escherichia and Shigella, Salmonella and Serratia and Escherichia and Salmonella.

This has great significance in transfer of antibiotic resistance genes carried on plasmids. When the plasmids are F-factors, the transfer occurs readily. Moreover, when the genes are attached to transposons, the transposons may "jump" from ordinary plasmids to F-factors, after which transfer may; occur. Conjugation may also occur in Gram-positive bacteria as Streptococcus mutans (a common case of dental cavities).

Only plasmids especially those carrying genes for antibiotic resistance are involved in this species. Similar observations have been made in Bacteroides and Clostridium species. Till now mechanism of plasmid transfer in Gram positive bacteria is poorly understood and chromosomal transfer is yet to be demonstrated

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