Transgen

Transgen, in genetics, broadly refers to a gene or genetic material that has been introduced into an organism from a different species or genomic background, or that has been relocated within the genome. In English usage, a transgene is the inserted DNA sequence, while a transgenic organism is one that carries one or more transgenes in its cells. The term is used in biology, agriculture, and medicine to describe organisms modified through deliberate DNA addition. In some languages, transgen or transgén may be used to refer to either the gene or the modified organism, but the distinction between transgene (the DNA) and transgenic (the organism) is common in scientific usage.

Transgenes are typically introduced using molecular biology techniques. DNA may be delivered by plasmid vectors or viral vectors and integrated into the host genome, often via transformation or transfection in cells, microinjection into embryos, electroporation, or particle delivery (biolistics). Advances in genome editing, such as CRISPR-Cas9, enable targeted insertion of a transgene at a chosen genomic location. Depending on the system, the transgene may be integrated into the genome or maintained on episomal DNA.

Applications of transgenic technology span multiple fields. In agriculture, transgenic crops may express traits such as pest resistance or herbicide tolerance, improving yield or management. In medicine, transgenes are used to produce therapeutic proteins in host cells and form the basis of gene therapy approaches that deliver corrective or protective genes to patients. Model organisms, such as mice, are engineered with transgenes to study gene function and human diseases.

Regulatory and safety considerations accompany transgenic work. Most jurisdictions require risk assessment, containment, and oversight of environmental or food-related releases, with frameworks varying by country. Ethical discussions and public engagement are common components of policy development in this area.