The recombinant DNA technology also called as genetic engineering, involves artificial modification of genetic constitution of a living cell by introduction of foreign DNA through experimental techniques. Recombinant DNA technology is a major DNA-based tool in which, a gene or multiple genes can be identified, cut, and inserted into the genome of another organism.

Recombinant DNA is the term applied to chimeric DNA molecules that are constructed in vitro, then propagated in a host cell or organism.

The tools which are required in recombinant DNA include vectors, restriction enzymes, ligases and host organism.

Steps

A recombinant DNA technology has five steps:

• (1) cutting the desired DNA by restriction sites,
• (2) amplifying the gene copies by PCR,
• (3) inserting the genes into the vectors,
• (4) transferring the vectors into host organism, and
• (5) obtaining the products of recombinant genes

A restriction enzyme is a DNA-cutting enzyme that recognizes a specific target sequence and cuts DNA into two pieces at or near specific site.

DNA ligase seals gaps in the DNA backbone.

Applications

For the production of recombinant human peptide hormones:-

These include highly publicized family of products of recombinant DNA technology. These include Insulin, Human growth hormone (HGH), Follicle stimulating hormone (FSH), Luteinizing hormone(LH), epidermal growth factors, gastrin, relaxin, neuropeptides (calcitonin) and secretin

In production of recombinant vaccines:

The recombinant technology is responsible for the production of vaccines for various diseases such as Hepatitis B, Influenza, cholera and leishmaniasis.

In anti sense therapy

Antisense therapy is therapy which uses a strand of nucleic acid (DNA,RNA or a chemical analogue) (synthesized nucleic acid is termed an “anti sense” oligonucleotide because its base sequence is complementary to the gene’s messenger RNA (mRNA), which is called the “sense” sequence) that binds to the mRNA produced by target  gene to inactivate and effectively turning target gene “off’.

Antisense drags are being researched to treat cancers, diabetes and diseases such as asthma and arthritis with an inflammatory component. One antisense drug, fomivirsen is used as a treatment for cytomegalovirus retinitis.