GENETIC ENGINEERING

During the late 1970s, the science of genetics entered the new era dominated by the use of recombinant DNA technology or genetic engineering to produce outstanding life forms that is not found in the nature. Through this technology, it has been possible to transfer genes from mammals into microorganism like bacteria, causing them to act like tiny factories for making proteins of great economic importance, such as hormones (including growth hormones) and interferon (lymphocyte proteins that prevent replication of a wide variety of viruses). These proteins are produced in such a small amount in humans that the cost of their extraction from tissue has been very expensive.
By genetic engineering it has become possible to produce various blood clotting factors, complement proteins (part of immune system) and other substances for the correction of genetic deficient diseases. Recently, experiments have been conducted in which human cells which are unable to synthesise purines have been obtained from the patient with Lesch-Nyhan Syndrome and grown in culture. These cells have been converted to normal cells by transformation with recombinant DNA.
Thus we can say that genetic engineering could be used as an application for the correction of human defects and providing gene therapy. The therapy given to the patients with the help of genetic materials is called gene therapy. For example, restoring the ability of a diabetic individual to make insulin or correcting immunological deficiencies come under gene therapy.
Recombinant DNA molecules are produced with one of the following three objectives:

1. To obtain a large number of copies of specific DNA fragment
2. To recover large quantities of protein produced by the concerned gene.
3. To integrate the gene in question into the chromosome of the target organism where it expands itself.

Steps Involved In Genetic Engineering

Genetic engineering involves six steps as follows:

1. Isolation of gene or other piece of DNA to be cloned.
2. Insertion of gene into another piece of DNA called a vector that will allow it to be taken up by bacteria and replicate within them as cells grow and replicate.
3. Transfer of recombinant vector into bacterial cells either by transformation or infection through transmission of virus.
4. Selection of those cells which contains desired recombinant vectors.
5. Growth of bacteria that can be continued independently to give as much clone DNA as needed.
6. Expression of gene obtained in the desired product.

Scope And Application Of Genetic Engineering

Genetic Engineering has been applied in several fields some of them are as follows:

• Contribution of Genetic Engineering in the field of medical science in order to get pharmaceuticals like Humulin (human insulin).
• Heamophaelics do not have factor eight which does not allow blood clotting or the blood takes long to clot. Genetic Engineering is used in their treatment to isolate factor eight from another source and introduce in the body of Haemophaelic patients.
• Erythropoetin induces RBC (Red Blood corpuscles) production, and person deficient in this protein/harmone are anaemic. Genetic code for this harmone is transferred into bacteria and reintroduced into the patients suffering from anaemia.
• Tissue Plasminogen Activator (TPA) activates plasmin which dissolves blood clots. Genetically engineered products are used for treating myocardial infection.
• Wounds caused by burns and brittle bones are treated by growth harmone which are produced and introduced through genetic engineering. Thus it can be realised that genetic engineering is also capable of treating person suffering from dwarfism.
• Genetic Engineering is also used for the treatment of cancer patients as it can be used for the production of interferon and interleukins.
• Genetic Engineering is used for vaccination purpose. In vaccination instead of introducing whole organism into the human body only genetically extracted portion of organisms, like bacteria and viruses which can elicit response and help in the production of antibodies against the antigens, is introduced. Vaccination programme has been started for eliminating Polio, DPT, Foot and Mouth disease etc.

for more information you can also refer to http://en.wikipedia.org/wiki/Genetic_engineering