A transgenic organism contains genetic material that has been deliberately introduced from a different species, conferring a new trait that is not normally present in that organism.
Mechanisms and Context
Transgenic organisms are produced by inserting a foreign gene, or transgene, into the genome of a host. The process begins with cloning the gene of interest into a vector that provides regulatory sequences for expression. Delivery methods include microinjection of DNA into fertilised eggs, infection with viral vectors, and transformation of cells followed by selection. If the transgene integrates into the germline, the trait can be passed to offspring. Random integration often leads to position‑dependent expression, whereas targeted insertion uses homologous recombination or genome editing tools such as CRISPR–Cas to place the transgene at a defined locus. Transgenic models are invaluable for studying gene function, modeling human diseases and testing therapeutics. In agriculture, transgenic crops are engineered for traits such as pest resistance, herbicide tolerance and improved nutrition. The term transgenic differs from cisgenic, where genes are transferred between closely related organisms. Regulatory oversight focuses on assessing the safety of transgenic organisms for human consumption and environmental impact, and ethical discussions consider potential effects on biodiversity and farming practices.
Notable Examples and Uses
Transgenic mice carrying human oncogenes or reporter genes are standard tools for exploring tumor biology and development. Bt cotton and Bt maize express an insecticidal protein from Bacillus thuringiensis, providing protection against specific pests and reducing pesticide usage. Golden Rice has been engineered to produce β‑carotene in the grain to help combat vitamin A deficiency. Fast‑growing Atlantic salmon contain a growth hormone gene that allows them to reach market size more quickly. Transgenic goats have been used to secrete anticoagulant proteins like antithrombin in their milk, while engineered bacteria produce recombinant human insulin for diabetes therapy. These cases illustrate the broad spectrum of transgenic applications in research, agriculture and medicine.
Transgenic technology expands the genetic repertoire of organisms beyond natural boundaries. It provides tools for basic science, medicine and agriculture, while raising important considerations about safety, ethics and regulation. Continued refinement of gene delivery and editing techniques is shaping the future of transgenic research.
Related Terms: GMO, genetic engineering, recombinant DNA, gene therapy, biotechnology