Genetic engineering is defined as the manipulation of genetic material towards a desired end and in a directed and predetermined way, using in vitro process.### According to John E. Smith (1996), genetic engineering as ‘the formation of new combination of heritable material by the insertion of nucleic acid molecule produced by whatever means outside the cells, into any virus, bacterial plasmid or other vector system so as to allow their incorporation into a host organism in which they do not occur naturally but in which they are capable of continued propagation’.