A genetically modified organism (GMO) is an organism whose genome has been altered in the laboratory by the insertion, deletion or modification of genetic material using biotechnology techniques.
Explanation
A GMO is created when scientists introduce DNA from the same species or a different species, or edit endogenous genes, to confer new traits or functions. Recombinant DNA technology involves cloning genes into vectors and transferring them into host cells; plants are commonly transformed using Agrobacterium tumefaciens or biolistic methods, while animals may be modified by microinjection, viral vectors or nuclear transfer. Modern genome‑editing tools, such as CRISPR–Cas9, TALENs and zinc‑finger nucleases, enable precise additions or deletions. GMOs are indispensable in basic research for studying gene function and in industry for producing pharmaceuticals and enzymes. Modified bacteria synthesize human insulin, growth hormone and chymosin for cheese production. Agricultural GMOs, such as Bt cotton and glyphosate‑tolerant soybean, express insecticidal proteins or herbicide resistance to improve yields and reduce pesticide use. Gene‑edited animals include disease‑resistant pigs and mosquitoes engineered to reduce malaria transmission. Regulatory frameworks require risk assessments before GMOs are released into the environment or food chain, and labeling policies differ worldwide. Ethical and socioeconomic debates address ecological impacts, food security, intellectual property and consumer choice. Advances in gene editing blur distinctions between GMOs and conventionally bred organisms, challenging existing definitions and regulations.
Examples and important facts
Genes encoding toxins from the bacterium Bacillus thuringiensis have been inserted into corn and cotton to confer resistance to lepidopteran pests. Crops known as Roundup Ready contain a modified 5‑enolpyruvylshikimate‑3‑phosphate synthase gene that renders them tolerant to the herbicide glyphosate. Recombinant yeast engineered with human genes produce vaccines, including the hepatitis B surface antigen. Gene therapy trials use adeno‑associated viral vectors to deliver corrective genes for disorders such as spinal muscular atrophy and inherited retinal dystrophy. The Flavr Savr tomato, approved in the 1990s, was engineered to express an antisense polygalacturonase gene, slowing fruit softening. CRISPR‑edited fish and livestock with enhanced growth rates are being developed, and gene drives in mosquitoes aim to reduce disease transmission.
Genetically modified organisms illustrate the power of biotechnology to endow organisms with new traits for research, medicine and agriculture. They also highlight the need for careful assessment of benefits, risks and ethical considerations.
Related Terms: Genetic engineering, Transgenic organism, Biotechnology, CRISPR, Gene therapy