Genetic Transformation of Bacteria and Yeasts
After DNA fragments are cloned in a vector, that recombinant vector must be incorporated into a microorganism in order to amplify, purify, or express the gene it contains. This incorporation is carried out by genetic transformation. The principle is to introduce into a bacterial cell (generally Escherichia coli) or eukaryotic cell (e.g., yeast) the recombinant vectors, i.e., those containing an exogenous DNA insert, obtained after cloning. When a recombinant vector is introduced into a new cell by genetic transformation, it can replicate there autonomously. In doing so, it replicates its DNA and also the DNA insert that it contains at the polycloning site.