Q. What is genetic engineering?

Genetic engineering, It is also known as molecular cloning or gene cloning, is artificial recombination of nucleic acid molecules in a test tube; their insertion into a virus, bacterial plasmid or other vector system; and subsequent incorporation of chimeric molecules into a host organism in which they are capable of continued propagation. Construction of such molecules hasalso been called gene manipulation since it usually involves production of novel genetic combinations by biochemical means. Genetic engineering techniques include cell fusion and the use of recombinant DNA or gene-splicing. In cell fusiontough outer membranes of sperm and egg cells are removed by enzymes, and then fragile cells are mixed and combined with aid of chemicals or viruses. Result may be the creation of a new life form from two species (a chimera). RecombinantDNA techniques transfer a specific genetic activity from one organism to the subsequent through the use of bacterial plasmids (small circular pieces of DNA lying outside the main bacterial chromosome) and enzymes, like restriction endonucleases (that cut the DNA strands); reverse transcriptase (that makes a DNA strand from an RNAstrand); DNA ligase (that joins DNA strands together); and Taq polymerase (that can make a double-strand DNA molecule from a single-strand "primer" molecule). Recombinant DNA process begins with the isolation and fragmentation of suitable DNA strands. After these fragments are combined with vectors, they are carried into bacterial cells, where DNA fragments are "spliced" on to plasmid DNA which has been opened up. These hybrid plasmids are then mixed with host cells to form transformed cells. Because only some of the transformed cells will exhibit desired characteristic or gene activity, transformed cells are separated and grown individually in cultures. This methodology has been successful in producing large quantities of hormones (like insulin) for biotechnology industry. However it is more difficult to transform plant and animal cells. Yet technique exists to make plants resistant to diseases and to make animals grow larger. As genetic engineering interferes withprocesses of heredity and can change genetic structure of our own species, there is much concern over ethical ramifications of such power, and possible health and ecological consequences of creation of these bacterial forms.