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These are foods - usually plants, though we're starting to see animals too - whose DNA has been modified to include genes from other organisms to produce a particular trait, such as disease or pesticide resistance.
GMOs have inspired a strong public backlash, despite the fact that those currently on the market have passed safety tests and are generally considered safe for us to eat.
But there are new forms of genetic modification that don't involve using genes from other species, and scientists are worried these could spur similar alarm from consumers.
Gene-edited crops vs. GMOs
These include the gene-editing tool CRISPR/Cas9, which works like a biological find-and-replace function to cut out genes and splice in new ones. In the last few years this technique and others have really taken off, and are already being used to develop potential treatments for genetic diseases.
But one of the first applications of this technology is likely to be in agriculture, as the world struggles to feed a growing population and deal with the dismal reality of climate change.
A recent commentary in the journal Nature Genetics outlines the differences between gene-edited crops (GECs) and GMOs, and lays out some rough guidelines for how to regulate the former.
As the journal's editors write in an accompanying editorial, "A distinction must be established, particularly in the public sphere, between 'genetically modified organisms' (GMOs) generated through the transgenic introduction of foreign DNA sequences and 'genome-edited crops' (GECs) generated through precise editing of an organism's native genome."
Genome editing is a more efficient and precise method of manipulating genes than the conventional breeding methods we have used for millennia, but the outcome is very similar. By comparison, GMOs contain DNA from other organisms, which would not be found in nature.
The commentary's authors are proposing that we regulate the product, not the technology used to create it.
However, they're not suggesting that gene-edited foods should be let off the hook completely - they believe GECs should be subject to the same registration process as traditionally bred crop varieties, but they shouldn't be subjected to additional government oversight, which could be unnecessarily restrictive, they say.
"The potential benefits of GECs should not be impeded as a result of misinformation, so disclosure and education are the best ways to promote sound policies," they write.
The opposition
But some people are already voicing their opposition to the new gene-editing technologies. Earth Open Source, a European NGO funded by the Maharishi cult, recently attacked the claim that CRISPR was more accurate than previous genetic engineering tools.
The nonprofit Genetic Literacy Project called this a "simplistic caricature" of the science, adding that " the cult's description has little to do with the use of the technology in plants."
David Stern, a plant biologist and president of the Boyce Thompson Institute for Plant Research, agreed with the commentary's guidelines, but warned in a statement released by the Genetic Expert News Service that people might perceive gene editing as "playing God."
"I think this is a price that must be paid for the many benefits gene-edited crops can bring to the agricultural space," Stern said.
If history is anything to go by, the road to gene-edited foods is likely to be a bumpy one.