Recombinant DNA technology, also known as genetic engineering or gene cloning, is a set of techniques used to manipulate and modify DNA from different sources to create new DNA molecules.
These recombinant DNA molecules are widely used in gene therapy, biotechnology, and pharmaceuticals.
Steps in Recombinant DNA Technology
1) Isolation of DNA
DNA is extracted from a source organism using enzymatic digestion or commercial extraction kits.
2) Cutting DNA
Restriction enzymes cut the DNA at specific sites, creating sticky or blunt ends that allow fragments to be joined with DNA from other sources.
3) Cloning Vectors
Vectors (e.g., plasmids or bacteriophages) carry foreign DNA into a host cell.
DNA fragments are inserted into vectors using sticky ends.
4) Transformation
The recombinant DNA is introduced into a host cell (e.g., bacteria) through transformation, allowing replication of the recombinant molecule.
5) Selection
Selection markers (e.g., antibiotic resistance genes) help identify host cells that successfully took up the recombinant DNA.
6) Screening
PCR, DNA sequencing, and Southern blotting verify the presence and integrity of the desired recombinant DNA.
Example: Production of Human Insulin
The insulin gene is isolated from human DNA.
It is inserted into a plasmid vector (e.g., pBR322).
The recombinant plasmid is introduced into E. coli.
The bacteria produce human insulin, which is later purified for medical use.
