Breakage of DNA molecule at two desired places to isolate a specific DNA fragment and then inserting it in another DNA molecule at desired position results in a new gene product which is called as recombinant DNA. In recent years techniques for manipulating euvaryotic as well as prokaryotic DNA have witnessed a remarkable development.
This has allowed breakage of DNA molecule at desired places to isolate a specific DNA fragment and then insert it in another DNA molecule at a desired position. This process of DNA recombination and technique is also called genetic engineering.
With this technique of recombination genes can be isolated, cloned and characterized. So, this technique has to lead to significant progress in all areas of molecular biology and with the help of this technique one can isolate and clone single copy of a gene or a DNA segment into an indefinite of copies. This becomes possible because bacteria, phages, plasmids etc. reproduce in their usual style even after insertion of foreign DNA, and the inserted DNA also replicate faithfully with the parent DNA. This technique is called gene- cloning.