Cloning is a process by which identical organisms are produced. Genetic makeup of close being identical shows no genetic variation. Microbial cloning result from the process of division of genetically altered or modified microbial cells. In biotechnological aspects, it is related to the process of creating clones of organisms or copies of cells or DNA fragments.

The self replicating small circular DNA molecules located within the bacterial cell outside the cellular DNA that is known as plasmid. This is used to clone DNA inserts up to 5 KB in size. It is a small extra chromosomal part of DNA molecule which is separated from chromosomal DNA.

Cosmid cloning vector is a cloning vector which is formed by fusion of cos region of lambda phage with a plasmid. This vector is capable of carrying large fragment of DNA of 28 to 45 kb in size. It is a type of hybrid plasmid that can be used to build genomic libraries.

Transgene is the foreign or modified gene that has been introduced into an organism. In the process of trans genesis, the transgenes are introduced in the organism. It has the potential to change the phenotype of an organism.