[NatashaKundi]

Genetic Engineering is the technique of biotechnology which helps in preparing recombinant DNA. DNA molecule is cut into small pieces in in vitro environment. There are numerous techniques which have been used in genetic engineering for example, recombinant DNA technology, microinjection, bioballistics, electro and chemical poration.

Techniques:-

Recombinant DNA:-

Following steps are involved in recombinant DNA technique;

1) Gene of interest is isolated from the DNA molecule using the restriction enzymes.
2) After isolation, gene is inserted into a vector and is cloned to make multiple copies of gene of interest.
3) When the cloning is done, the gene is incorporated into the plasmid.
4) Now the gene or DNA along with the plasmid is called as recombinant DNA.

Plasmids and vectors used for the recombinant technique are usually bacteria or viruses. They have the ability to carry foreign genes into the host cell where they release the gene of interest and this gene replaces the diseased gene.

Plasmid is a circular piece containing the genetic material. When new gene is inserted in it, it opens it ring and new gene is attached to its ends through the enzyme called as ligase. New gene replicates along with the plasmid’s genetic material. For example if plasmid is carrying a gene of insulin, t will start producing the protein of insulin along with other gene products. Bacteria are of great significance in the pharmaceutical industry because they are used to produce insulin and other useful proteins.

Vectors are usually viruses which are also helpful in genetic engineering. Virus is an infectious organism, so when a new gene is inserted in it, it transfers that gene into the host cell during causing infection. Scientists mostly block the function of virus when they insert the foreign gene; this way virus will only be able to replicate only the gene of interest and will insert it into the host cell.

Electro and chemical poration:-
In this method, pores are created in the membrane of the cell and genes can be transferred easily. Special chemicals are used to make pores in the cell surface. Sometimes cells are exposed to weak electric current, it also makes pores in the surface of the cells and genes can easily pass through these pores.


Bioballistics method:-
In this method, small silver particles are used to insert the genetic material into the recipient cell. These silvers are coated with the genetic material and when released in the cell, genetic material incorporates with the genes of the host cell. In one projectile method, shot gun is used to insert the silvers into the host cell.

Microinjection:-
It is not necessary that only plasmids and vectors should be used for the transfer of genes into the cells. There are methods which are not dependent on plasmids and vectors. One of these methods is microinjection. In this method, foreign gene is integrated into the cell by just injecting it into the recipient cell. When large cell of plants and animals are concerned, then a fine glass needle is used. The injected genes automatically enter into the nucleus where they incorporate with the host cell’s genetic material and replicate.