DNA cloning is the starting point for many genetic engineering approaches to biotechnology research.
Get information sheet: Polymerase chain reaction (PCR)
How is DNA cloned in cells?
The four main steps in DNA cloning are:
Step 1. The chosen piece of DNA is ‘cut’ from the source organism using restriction enzymes.
Get information sheet: Restriction enzymes
Step 2. The piece of DNA is ‘pasted’ into a vector and the ends of the DNA are joined with the vector DNA by ligation.
Get information sheet: DNA ligation
Step 3. The vector is introduced into a host cell, often a bacterium or yeast, by a process called transformation. The host cells copy the vector DNA along with their own DNA, creating multiple copies of the inserted DNA.
Get information sheet: Bacterial transformation
Step 4. The vector DNA is isolated (or separated) from the host cells’ DNA and purified.
DNA that has been ‘cut’ and ‘pasted’ from an organism into a vector is called recombinant DNA. Because of this, DNA cloning is also called recombinant DNA technology.
What is cloned DNA used for?
DNA cloning is used to create a large number of copies of a gene or other piece of DNA. The cloned DNA can be used to:
- Work out the function of the gene
- Investigate a gene’s characteristics (size, expression, tissue distribution)
- Look at how mutations may affect a gene’s function
- Make large concentrations of the protein coded for by the gene
What other types of cloning are there?
The term ‘cloning’ is also used to describe other laboratory processes:
- Reproductive cloning is the process of making a genetically identical copy of an organism.
- Therapeutic cloning is the process of making multiple copies of a cell to treat a disease.
- 28 November 2007