Conjugation, Transformation and Transduction.

- TRANSFORMATION: process by which a donor DNA molecule is taken up from the external environment and incorporated into genome of recipient cell. Allows for Recombinant DNA Technology. Involves use of plasmids. - TRANSDUCTION: Involves transfer of genetic material from one bacterium to another by a bacteriophage. Acting as a vector, the virus carries its own genome plus a fragment of DNA from the bacterium it has recently infected. If the host bacterium survives the viral attack, recombination may occur,

Conjugation

Bacterial conjugation is the temporary direct contact between two bacterial cells leading to an exchange of genetic material (DNA). This exchange is unidirectional, i.e. one bacterial cell is the donor of DNA and the other is the recipient. In this way, genes are transferred laterally amongst existing bacterial as opposed to vertical gene transfer in which genes are passed on to offspring.

The F (fertility) factor is a circular double stranded DNA molecule of around 100 x 103 base pairs. Bacterial cells with the F factor, denoted as an F+ cell, are capable of transferring genes to an F- cell (without F-factor) by means of conjugation (Fig. 1).