With the interpretation of genetic code by Hargobind Khorana an India born American scientist in 1968, for which he received Nobel Prize mere hopes were changed into a real approach to gene therapy. The con­cept of hereditary factors in all biological species came from Austrian Botanist Gregor Johan Mendel in eighteen eighties. The name genes were given to these factors by Wilhelm Johannesen, a Danish biologist. The nomenclature became firm. Later research in the field established that genes have many functions. An important one is the formation of a large number of proteins. The genes, the scientists say, mastermind the whole process of life in all living creatures. Still it was shrouded with mystery till 1953 when J. D. Watson and Francis Crick discovered the structure of Deoxyribonucleic Acid (DNA). DNA is a complex nucleoprotein. It contains body’s 50,000 to 100,000 genes. These genes are arranged in a pattern that is unique to each individual. It is this peculiarity that makes every individual different from the other.

Different genes in different parts of the body have different func­tions. The gene for a particular trait is placed at a particular location in the chromosomes. Moreover, the genes play an important role of manu­facturing thousands of different proteins from 20 amino acids. The genes, thus govern the immune system too. One can just guess how many prob­lems can be created in the body if any particular gene is broken, is dis­eased or is eliminated. Treating, slicing, removing and transplanting genes is known as Genetic Engineering.

It was formerly a part of science fiction. But with a successful experiment on a four year old girl at National Institute of Health, Bethseda in USA the decoding of the mystery of genes began on September 14, 1990. The girl was born with no natural protection against disease as her immune system lacked a particular gene responsible for it. Her blood cell was taken and altered to contain the particular gene, was multiplied and she was injected with one billion of her own blood cells. In another case the doctors altered genes to counteract malignant melanoma. It is a fatal disease. A cell known as tumour infiltrating lymphocytes was removed and a gene that manufactures a cancer fighter was inserted in it. These cells were reproduced by millions and injected into the patient. The re­sults have been very encouraging.

Dr. Thomas Caskey of the Baylor University College of Medicine in Houston is a pioneer in the method of introducing a crippled virus with a corrected gene into body of a patient. He has specialized it in bone marrow transplantation. Dr. J. M. Ronald Crystal of the National Heart, Lung and Blood Institute used the same system to correct a genetic flaw that causes the lung infection. A thick mucous deposit in the lungs stop­ping its function. Research at Stanford University and Michigan Univer­sity show that muscle cells can also be genetically altered. Experiments have been successfully made at Ohio University on rodents to provide genetic protection against leukemia.

Researches in different countries in the world have estimated that there are about four thousand disorders because of defects in genes. These may be at the time of birth or may develop in later years. If the researches continue with the same spirit and enthusiasm it is a question of a few decades that Genetic Engineering will replace the conventional treatments in the medical world for the cure of a large number of diseases.