Recombinant DNA is achieved by cleaving pro-DNAs by

Restriction enzymes are DNA-cutting enzymes found in bacteria and harvested from them for use. Because they cut within the molecule, they are often called restriction endonucleases. A restriction enzyme recognizes and cuts DNA only at a particular sequence of nucleotides. So, restriction endonucleases are used for separation of genetic material. During the process of recombinant DNA technology, the same restriction enzyme is used to the donor DNA and small circular molecules act as carriers, or vectors for the DNA fragments which is also called as pro-DNAs and joined together. The vector molecules with their inserts are called recombinant DNA because they consist of novel combinations of DNA from the donor genome (which can be from any organism) with vector DNA from a completely different source.