There is no single method of recombinant DNA technology, but it involves several steps as given below:

1. Isolation of DNA (also called insert DNA, target DNA, foreign DNA) of known function from an organism (A).

2. Enzymatic cleavage (B) and joining (C) of insert DNA to another DNA molecule (cloning vector) to form a recombinant DNA (i.e. vector + insert DNA) molecule (D).

3. Transformation of a host cell i.e. transfer and maintenance of this rDNA molecule into a host cell (E).


4. Identification of transformed cells (i.e. cells carrying rDNA) and their selection from non- transformants .

5. Amplification of rDNA (F) to get its multiple copies in a cell.

6. Cell multiplication (G) to get a clone i.e. a population of genetically identical cells. This facilitates each of clones to possess multiple copies of foreign DNA.