A genetically modified organism (GMO) is an organism whose genome has been intentionally altered using recombinant DNA techniques.
Modern molecular tools allow genes to be inserted, removed or edited in living organisms. Genetic modification typically involves the construction of recombinant DNA that carries a gene of interest under the control of regulatory sequences, followed by its introduction into a host genome through methods such as transformation, transfection, microinjection or viral vectors. The inserted gene (a transgene) can originate from a different species, enabling traits that would not arise through conventional breeding. Deletions or targeted changes can also be made using genome editing systems like CRISPR‑Cas9. Genetic modification has been used to produce microbes that synthesise pharmaceuticals, plants with improved agricultural traits and animals for research or food. Regulatory frameworks govern the development and release of GMOs to ensure safety and traceability. Debates about GMOs centre on environmental impacts, food safety, intellectual property and social acceptance.
Applications and Examples
Recombinant bacteria were first engineered in the 1970s and are now widely used to produce insulin, clotting factors and vaccines. Crops engineered to express a Bacillus thuringiensis toxin (Bt cotton, Bt corn) resist insect pests, reducing the need for chemical pesticides. Herbicide-tolerant soybean lines allow farmers to control weeds with specific herbicides. Biofortified rice known as Golden Rice expresses genes for beta‑carotene synthesis to address vitamin A deficiency. Genetically modified salmon (AquAdvantage) grow faster due to an introduced growth hormone gene. In public health, gene drive systems and engineered Aedes mosquitoes aim to suppress disease transmission. In medicine, ex vivo modification of T cells with chimeric antigen receptors (CAR‑T) allows targeted cancer therapies.
GMOs represent a broad class of organisms created through precise genetic manipulation. They provide tools for biotechnology, medicine and agriculture, while also raising important ethical and ecological considerations.
Related Terms: Transgenic organism, Biotechnology, Gene editing, Recombinant DNA, Crop