There are various methods of making the host cell competent for transformation with Recombinant DNA technology.
Microinjection method is one where the recommended DNA is directly injected into the nucleus of the animal cell. In the gene gun method, the bombardments on plant cell with high-velocity microparticles of gold or tungsten coated with DNA is done which is known as biolistic or gene gun.
The pathogen vectors are allowed to infect the cell and transfer the recombinant DNA into the host cell which is known as the retroviral vector method.