What is recombinant DNA?

Recombinant DNA (rDNA) are DNA molecules formed deliberately by laboratory methods (such as molecular cloning) to combine genetic materials from different sources, creating new sequences that would not otherwise be found in the genome. The difference between recombinant DNA and naturally occurring genetic recombination is that the former is created by artificial methods while the latter is a normal biological process existing in essentially all organisms.

The source of recombinant DNA can be from any species, such as plant, bacteria, human and fungal. If the DNA sequence does not occur in nature, it can even be created by the chemical synthesis of DNA. With recombinant DNA technology and synthetic DNA, literally any DNA sequence may be created and introduced into living organisms.