GMO
Genetically Modified Organism - a plant, animal, or microorganism whose genetic material has been altered using recombinant DNA technology to introduce traits that would not occur through natural breeding.
A genetically modified organism (GMO) has been altered by inserting genetic material from a different organism - sometimes a completely different species - using recombinant DNA technology. This distinguishes GMOs from conventionally bred plants and from hybrids. Hybridization combines genetics from the same species through natural pollination mechanisms. Genetic modification directly inserts specific genes, sometimes from bacteria or other kingdoms of life, bypassing the limits of sexual reproduction.
How GMO Crops Are Created
The most common method for plant modification is Agrobacterium-mediated transformation: a naturally occurring soil bacterium (Agrobacterium tumefaciens) has the ability to insert segments of its own DNA into plant cells. Scientists replace the bacterium’s natural DNA insertion with the desired gene and infect plant tissue culture. Some of the cells incorporate the new gene and can be grown into complete plants carrying the modification.
Another method, the gene gun, physically fires microscopic DNA-coated particles into plant cells.
Common GMO Traits in Commercial Agriculture
| Trait | Description | Crops |
|---|---|---|
| Herbicide tolerance (HT) | Resistance to specific herbicides (glyphosate, glufosinate) | Corn, soybeans, cotton, canola, sugar beets |
| Insect resistance (Bt) | Expression of Bacillus thuringiensis proteins toxic to specific insects | Corn, cotton |
| Virus resistance | Coat protein-mediated resistance to specific viral pathogens | Papaya (Rainbow variety), squash (limited) |
| Delayed ripening | Reduced polygalacturonase enzyme activity slows softening | Some tomatoes (limited commercial use) |
GMOs in the Home Garden
No GMO vegetable seeds are sold to home gardeners. The GMO crops in commercial agriculture (corn, soybeans, canola, sugar beets, cotton) are field crops grown on industrial scale, not garden vegetables. The sweet corn you buy from a seed catalog is conventionally bred, not GMO. The tomatoes, peppers, cucumbers, and squash at any retail seed company are non-GMO.
Rainbow papaya (Carica papaya ‘Rainbow’ and ‘SunUp’) is the only widely available GMO that a home grower might plant. This papaya variety was developed in the 1990s to save Hawaii’s papaya industry from papaya ringspot virus and is still grown in Hawaii. It’s GMO, clearly labeled, and its existence saved an entire regional agricultural industry.
GMO vs. Hybrid
The two are completely different and frequently confused. A hybrid is the offspring of two plants from the same species, produced by natural pollination. No foreign genes are inserted. A GMO has genes inserted from a different species using laboratory techniques.
You can have:
- OP non-GMO (heirlooms, most garden vegetables)
- Hybrid non-GMO (most commercial vegetable F1 varieties)
- GMO (Rainbow papaya, commercial commodity crops)
Regulatory Status
In the US, GMO crops are regulated by USDA, EPA, and FDA depending on the nature of the modification. The National Bioengineered Food Disclosure Standard (effective 2022) requires labeling of foods containing genetically modified ingredients above detection thresholds. Seeds themselves are not directly regulated under that disclosure standard but are subject to USDA oversight.