The short definition of a transgenic organism is a cell or organism whose genome has been altered through the artificial introduction of one or more foreign DNA sequences from another species. However, according to the National Human Genome Research Institute, transgenic organisms are primarily developed in laboratories for research purposes.
A key milestone in the history of genetically modified organisms (GMOs) was the discovery of Agrobacterium tumefaciens, a soil bacterium capable of infecting plant cells and transferring a specific segment of its DNA into them. This bacterium is also responsible for crown gall disease in plants.
The Dawn of Modern Biotechnology
The development of genetically modified organisms marked the beginning of a new branch of science: modern biotechnology. This field encompasses various methods of manipulating genetic information.
“It’s not always about inserting genetic material from one species into another, but rather about creating something new that doesn’t exist in nature, with a specific human-interest purpose, usually in production,” explains Ana Wegier, a researcher at the Botanical Garden of the Institute of Biology, UNAM.
Molecular Mechanisms Behind Genetic Modification
The discovery of the DNA double helix in 1953 paved the way for molecular tools that helped scientists understand recombinant and non-recombinant DNA.
“To create recombinant DNA, you need specific molecular scissors, so to speak. This was made possible by the discovery of restriction enzymes in certain microorganisms, which use them as a defense mechanism. There are also other enzymes called ligases, which—as the name suggests—allow DNA segments to be joined together,” explains Paola Angulo, a professor and researcher in the Department of Bioengineering and part of the Food Security research initiative at Tecnológico de Monterrey.
When a cell incorporates a new gene into its DNA, its genetic material is reorganized and modified, potentially granting it new characteristics. Transgenic organisms exist because cells can integrate genes from other living beings. This is possible because DNA has a universal structure across all organisms, enabling natural incorporation.
If a foreign DNA fragment enters a cell and is not degraded, it can integrate into the genome through a process known as genetic recombination. The new DNA then becomes part of the host organism, granting it the properties associated with that gene, as explained in Transgénicos, grandes beneficios, ausencia de daños y mitos (2017), a book coordinated by Francisco Bolívar Zapata and published by El Colegio Nacional.
In 1973, geneticists Stanley Cohen and Herbert Boyer created the first transgenic organism by inserting a fragment of frog DNA into a bacterial plasmid (used as a vector for molecular cloning of transgenes) and introducing it into Escherichia coli, as documented in the book.
“With these recombinant DNA methodologies, biotechnology reached a new dimension. Thanks to them, scientists could isolate specific genes from any organism, amplify them, and introduce them into another via horizontal DNA transfer, generating transgenic or genetically modified organisms,” the publication states.
In 1983, researcher Mary-Dell Chilton led the team that developed the first genetically modified plant, demonstrating that a bacterial cell could transfer DNA to a plant cell.
How Genetic Modification Differs from Selective Breeding
Wegier emphasizes the importance of distinguishing between genetically modified organisms and other genetic improvement techniques that do not have the same effects, such as hybridization or phenotypic selection—the latter referring to the identification of observable traits.
Selective breeding involves choosing genetic variants or strains based on their phenotypes (rather than their genomes) through repeated selection and breeding. According to the 2023 article Genetic Engineering and Genome Editing in Plants, Animals, and Humans: Facts and Myths, published in Gene,
“Organisms that undergo natural selection experience random genetic changes over long periods and are phenotypically selected by nature to better adapt to their environment.”
Both genetic engineering and selective breeding require human intervention, the article explains, but they conceptually resemble natural selection in producing new genetic variants in plants and animals.
Precautionary Measures and the Role of Bioethics
Angulo highlights the importance of applying precautionary principles when dealing with genetically modified organisms and considering bioethical implications. Each case and context in which transgenic organisms are introduced into an ecosystem should be carefully analyzed.
“For example, imagine arriving in a jungle and deciding to cut down all the tall trees to extract a compound. The lower vegetation would be negatively affected because it has adapted to the shade and humidity provided by those trees. That kind of adaptation doesn’t happen quickly or easily,” the biotechnologist explains.
She emphasizes that everything in nature is the result of millions of years of evolution, with a high degree of adaptation to selection pressures, fitness, and environmental constraints.
“This process is called genetic drift—it determines which genes persist and which are eliminated. Nature selects genes that no longer serve a purpose, ensuring that every aspect of a habitat is highly designed and integrated to coexist and sustain future generations.”
For Angulo, evolution is a powerful force, and humans must be mindful of their impact.
“It’s like cutting in line—we arrive thousands of years later and say, ‘Here’s my transgenic organism, let’s plant it here.’ That can have significant environmental consequences.”
GMOs in Everyday Life
Today, genetically modified organisms are part of daily life, particularly in pharmaceuticals. For instance, insulin, interferon (used to treat herpes and certain cancers), and vaccines against infectious diseases like hepatitis and influenza rely on genetic modification, according to Bolívar Zapata’s book.
Similarly, some genetically modified crops are grown in just 29 countries, according to a 2022 report by the Food and Agriculture Organization (FAO). These crops, which include soybeans, canola, potatoes, papayas, and corn, are directly or indirectly consumed worldwide. Other genetically modified plants, such as cotton, have also benefited from genetic sequencing technologies.
However, to ensure the highest levels of food safety, international regulations—such as the Cartagena Protocol—govern the handling, export, and consumption of genetically modified organisms, alongside each country’s specific legislation.
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