Recombinant DNA refers to DNA molecules created by joining genetic material from different sources to form sequences that do not occur naturally, enabling the cloning and expression of specific genes.
Explanation
The concept of recombinant DNA emerged in the early 1970s when researchers discovered that restriction endonucleases could cut DNA at defined sequences and DNA ligase could join fragments together. By combining a gene of interest with a cloning vector such as a plasmid, scientists can introduce the construct into host cells, replicate it and express the encoded protein. The typical workflow involves isolating the donor DNA, digesting both donor and vector with compatible restriction enzymes, ligating the fragments to form a recombinant plasmid and then transforming bacteria or other hosts. Selectable markers and screening methods identify cells that carry the recombinant DNA. Alternative assembly techniques include Gibson assembly and Golden Gate cloning. Once inside a host, the recombinant sequence can direct production of proteins, generate transgenic organisms or modify genomes. Recombinant technology underpins much of modern biotechnology and has transformed medicine, agriculture and research.
Applications and Examples
Recombinant human insulin was one of the first commercial products produced by inserting the human insulin gene into Escherichia coli. Recombinant factor VIII and erythropoietin are used to treat haemophilia and anaemia. Vaccines for hepatitis B and human papillomavirus employ recombinant viral proteins expressed in yeast or insect cells. Genetically modified crops such as Bt corn contain bacterial genes encoding insecticidal proteins, reducing pesticide use. In research, recombinant DNA allows overexpression or deletion of genes to study their function, and gene therapy approaches use viral vectors carrying therapeutic genes to correct genetic disorders. The technology also enables production of monoclonal antibodies and industrial enzymes.
Recombinant DNA technology combines precise enzymatic tools and host systems to manipulate genetic material. Its versatility has made it central to genetic engineering, pharmaceutical production and the study of gene function.
Related Terms: Genetic engineering, Plasmid, Cloning vector, Restriction enzyme, Biotechnology