Transgenes

Transgenes are DNA sequences introduced into an organism that originate from a different species or are artificially constructed. As a functional unit, a transgene typically includes a coding sequence and regulatory elements such as a promoter and terminator to drive expression. Transgenes may be integrated into the host genome or carried on an expression vector, and their activity can be controlled to target specific tissues or conditions. Delivery methods include plasmids and viral vectors in animal and human research, Agrobacterium-mediated transfer or particle bombardment in plants, and genome editing tools that insert the transgene at defined genomic locations.

Transgenic organisms are used in basic research, medicine, and agriculture. In agriculture, transgenes can confer pest resistance, herbicide tolerance, or improved nutritional profiles. In biomedicine, transgenes enable production of therapeutic proteins, development of disease models, and exploration of gene function. Reporter genes and selectable markers are commonly included to identify successful integrations.

Expression outcomes depend on insertion site and regulatory compatibility, and transgenes can cause unintended effects on nearby genes or traits. Biosafety, environmental impact, and ethical considerations shape regulatory oversight and public acceptance. Advances in precise genome editing have blurred the boundary with non-transgenic approaches, as some edits add explicit foreign DNA while others modify endogenous sequences without introducing new genes.