Transfer of DNA between cells

Within molecular biology transformation is genetic alteration of a cell resulting from the direct uptake incorporation and expression of exogenous genetic material from its surroundings and taken up by the cell membranes. The Transformation occurs naturally in some species of bacteria but it can also be affected through artificial means in other cells. Transformation to happen bacteria must be in a state of competence that might occur as a time-limited response to environmental conditions such as starvation and cell density. The DNA material can be transferred among different strains of bacteria in a procedure which is called horizontal gene transfer. Any species upon cell death release their DNA to be taken up by other cells; however transformation works best with DNA from closely associated species. These naturally competent bacteria carry sets of genes which provide the protein machinery to bring DNA across the cell membranes. Transport of the exogeneous DNA into the cells may need proteins which are involved in the assembly of type IV pili and type II secretion system as well as DNA translocase complex at the cytoplasmic membrane.

The Transformation is one of three processes through that exogenous genetic material may be introduced into a bacterial cell the other two being conjugation transfer of genetic material among two bacterial cells in direct contact and transduction injection of foreign DNA by a bacteriophage virus into the host bacterium. Transformation may also be used to define the insertion of new genetic material into nonbacterial cells including animal and plant cells however because transformation has a special meaning in relation to animal cells indicating progression to a cancerous state the term should be avoided for animal cells when describing introduction of exogenous genetic material. The Introduction of foreign DNA into eukaryotic cells is often called transfection.