Transfer of rDNA into a Suitable Competent Host

The recombinant DNA is now introduced -- transferred -- into a competent host cell of a suitable cloning organism, usually a bacterium, so that the inserted gene can be expressed. The host cell takes up the naked rDNA through a process called transformation and incorporates it into its own chromosomal DNA, which eventually leads to expression of the trait carried by the passenger DNA. This transfer of rDNA into a bacterial cell is assisted by divalent Ca2+ ions. In plant biotechnology, the cloning organisms most often used are E. coli and Agrobacterium tumefaciens. A host or competent cell that has successfully taken up the rDNA is now called a transformed cell. …