What is recombinant DNA and give an example?

• A. DNA formed by joining DNA from two or more sources; e.g., inserting a human gene into a plasmid for expression in bacteria.
• B. DNA that is replicated within a cell.
• C. DNA sequences found only in plants.
• D. DNA damaged by UV light.

Answer: (A)

Recombinant DNA is formed when DNA from two or more sources is joined into a single molecule, creating a new combination of genetic material. This makes it possible to move a gene from one organism into another and have it produced there. A classic example is inserting a human gene into a plasmid vector and introducing that plasmid into bacteria; the bacteria then use their machinery to express the human protein, such as insulin, which can be produced and harvested. In labs, enzymes are used to cut and splice DNA, and the plasmid acts as a carrier to deliver the gene into the host cell. The other options describe normal DNA replication, plant-specific DNA, or DNA damaged by UV light, none of which involve combining DNA from different sources.