What is Genetic engineering?

Genetic engineering is a technique of manipulating the DNA in cells to endow an organism with qualities it did not naturally possess. The technique is also called gene manipulation. It entails a number of steps the first of which is the constitution of DNA segment from nucleic acid molecules in a test tube. The length of DNA so made is inserted into a virus or some other suitable vector that can serve as a molecular ferry to carry it into the host organism. The crucial factor here is ability of the inserted DNA molecule to express itself and also to multiply. Bacteria and even higher animals may be genetically engineered to produce foreign proteins of interest by inserting a copy or multiple copies of the gene coding for the protein into them. Several important products of medical use such as insulin and the human growth hormone are now being produced commercially using genetically engineered bacteria. ‘Tracy’, a genetically engineered sheep produces the pharmaceutically important protein called Alpha-1 antitrypsin in her milk. Genetic engineering may be used to boost growth, alter resistance to factors such as drugs, heat, cold and salinity in both animals and plants.