Can A 10,000-Year-Old GMO Change How We Think About GMOs?

Researchers at Ghent University in Belgium have discovered ancient transgenic DNA from Agrobacterium in the sweet potato genome. The finding that DNA from the same microbe used to produce human-made transgenic crops—or genetically modified organisms, GMOs—resides in one of the world’s most important crops calls into question the classification of GMOs as unnatural. This new research could challenge the basis for regulating GMOs separately from non-transgenic crops and perhaps help rescue GMOs from their increasingly negative public image.

That is, if biotech advocates can harness this story to retell the GMO narrative from a new perspective.

The sweet potato was domesticated 8,000-10,000 years ago in South America, and today more than 100 million tons are grown every year around the world. It is grown for its fleshy storage root and leafy greens and, despite the name, is unrelated to the potato.  

While searching for regulatory bits of DNA in the sweet potato genome, the Belgian scientists discovered portions strikingly similar to well-known segments of DNA inserted by the bacteria Agrobacterium. Agrobacterium is a plant parasite. It inserts short sections of its DNA into plant cells that reprogram them to grow tumor-like structures called galls, which are often seen on tree trunks or crop plants. These galls are where the bacteria thrives when it gets the chance.

That Agrobacterium DNA might be in a crop plant is neither new nor altogether surprising. It has been found in tobacco before, although not in food crops. And a lot of DNA detritus floats around all of our genomes—viral DNA that does not function anymore, or truncated genes that are DOA.

But these microbial genes in sweet potato are actually active, albeit at a low level. What’s more, in studying hundreds of domesticated and wild sweet potato relatives, the researchers found that all of the crop plants, and none of their wild relatives, had one portion of this transgenic DNA. Although not proof, this strong association between the Agrobacterium DNA and the plants humans have domesticated is good evidence that the foreign DNA was selected for. That is, it might have helped produce a trait that humans kept around when taming sweet potatoes.

However, the scientists did not find a clear link between the DNA and the root we eat. It might be that the bacterial DNA produced stronger sweet potato plants, or conferred other useful traits, even if it does not account for the engorged root.

As a new lesson in the malleability of genomes during evolution, this study is fascinating enough. But the reason it was the cover of the latest issue of the Proceedings of the National Academy of Sciences has much more to do with the article’s final sentence:

“This finding could influence the public’s current perception that transgenic crops are ‘unnatural.’”

But will it?

In a recent survey by the Pew Research Center comparing the opinions of scientists and the general public, no topic—not vaccines, not evolution, not climate change—had as big of a gap between the two groups as whether GMOs are safe to eat. Google “GMOs” and the first hit is the non-GMO Project. Switch over to images and you’ll find that one syringe in a tomato just doesn't cut it these days, we've upped it to three!

Clearly companies like Monsanto, Syngenta and Bayer failed, and failed hard, in their consumer-oriented communication. They’re trying to make up for lost time. But the general public are not their customers, farmers are. And by the numbers, corn, cotton and soybean farmers sure like GMOs, so much so that 9 in 10 of each of these crops in the United States is genetically engineered. If biotech advocates want to pivot the conversation in the public sphere, this article could be that fulcrum. But there are no guarantees it will work.

Already the popular press has written it up and jump-started the conversation in a positive light. Biotech advocates should call into question the unnecessary exclusion of GMOs from the USDA organic label. Are organic sweet potatoes still a thing? If the organic label was changed to be exclusively about growing practices and not germplasm, we could have organic GMOs, as envisioned by rice geneticist Pamela Ronald and her organic farmer husband Raoul Adamchak.

Biotech advocates should call into question the label of GMO. Period.

This sweet potato study blurs the already unclear boundaries between crops created by artificial selection, induced mutation, hybridization, and genetic engineering. New genetic engineering methods that introduce no foreign DNA muddy the waters even more. By some definitions, organic sweet potatoes will be GMOs while genetically engineered potatoes won’t be. Before we start playing definitional Twister, let’s simplify the conversation so we can speak meaningfully about what matters—allergenicity, gene escape, industrial agriculture, and feeding billions of people healthfully in the era of climate change.