Which technique is utilized to introduce recombinant DNA into animal cells?

Microinjection

The correct answer is Option (2) -Microinjection

There are several methods to introduce alien DNA into host cells. One such method is micro-injection, where recombinant DNA is directly injected into the nucleus of an animal cell.

In another technique, suitable for plants, cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA. This method is known as biolistics or gene gun.

The third method involves the use of "disarmed pathogen" vectors. In this approach, vectors derived from pathogens, such as Agrobacterium tumefaciens for plants or retroviruses for animals, are modified to be non-pathogenic. When these vectors infect the host cells, they transfer the recombinant DNA into the host's genome.

Each method has its advantages and limitations, and the choice of technique depends on the type of host cell and the specific requirements of the genetic modification.