Research on genetic engineering is centered on in vitro joining of DNA fragments of different origins by the mediation of some highly specific enzymes to produce ‘recombinant-DNA’ which is then introduced into appropriate hosts wherein it multiples (gene cloning). Thus the genetic engineering is also called “recombinant-DNA technology”.

Thus way immense possibilities are raised to bring about new gene combinations not occuring in nature. The science of recombinant-DNA technology or genetic engineering is still its infancy. Even then, its enormous potential impact both social and commercial, are clearly evident.

At present the microorganisms dominate in the sphere of this fascinating technology. Most of the basic informations regarding this novel approach has been through microorganisms. Restriction enzymes, the enzymes that cleave DNA molecules to obtain desired genes, are obtained from microorganisms and so are the ligases that are used in joining the DNA fragments.

Almost all the vectors, the vehicles that carry genes (DNA fragments) from donor DNA to recipient DNA, are microbial; for example, plasmids, cosmids, plasmids and viral vectors. Not only these but, there are microorganisms which are predominantly cloned with new genes to produce products of choice.