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GMO Facts and Fiction

Donate See if you know how many of these GMO "facts" are right.  

by Brian Dunning

Filed under General Science, Health

Skeptoid Podcast #454
February 17, 2015
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GMO Facts and Fiction

No matter how many articles are published detailing how and why genetically engineered crops are safe, misinformation always seems to reign. Anti-biotech activists persist in charging GMO crops (Genetically Modified Organisms) with just about every crime against humanity, ethics, and science. Although Monsanto is the company drawing nearly 100% of the flak from anti-biotech activists and is probably the only genetic engineering company known to most people, it's actually only one of the six biggest companies that develop GMO crops. The others are DuPont-Pioneer, Syngenta, Dow Agrosciences, BASF, and Bayer Cropscience. Beyond the big six, about 20 other smaller companies located all around the world are also in the business. But don't expect to go down to the local nursery and find seeds branded with these names: like most manufacturers, they all sell under a variety of more customer-friendly brands. Monsanto, the market leader among the big six, sells 15 different brands, each tailored to specific products or regions. What happens to all these brands of seeds that get bought, sown, and reaped? See if you can guess all of these "fact or fiction" choices right, starting with:

Supermarkets are full of GMO foods.

True, but mostly as ingredients in prepared food. About 85% of three major food crops grown in the US — corn, soy, and cotton — are GMO. Most of the produce you buy (corn and soybeans being the only real notable exceptions) are currently not GMO. Another exception is the papaya. Most of the papayas available in the United States come from Hawaii, where the ringspot virus decimated the species in the mid 1990s. But in 1998, a crop scientist found a way to insert a single ringspot gene into the papaya, thus conferring natural immunization; and now the Hawaiian papaya flourish.

But beyond those three examples from the produce aisle, it's pretty hard to find a prepared food product that contains no corn, soy, or cottonseed products, so the answer is yes. If you live in the Americas, you've been eating a lot of GMO food from the supermarket for the past several decades.

GMO leads to monoculture.

False. Supply and demand is what leads to monoculture, and that's got nothing to do with GMOs. Monoculture is when you plant the same crop over and over again in the same field, without rotating. Rotating crops naturally prevents the most common pathogen and pest antagonists to gain a foothold on any particular crop, and keeps the soil as healthy as practical. Farmers have understood the benefits of crop rotation since at least 6000 BCE. If there was an equal demand for corn, soy, and cotton, farmers would be able to rotate perfectly and everything would be hunky dory.

Sadly that's not the case. In 2011, the United States had 84 million acres of corn; 74 million acres of soybeans, 56 million acres of hay, 46 million acres of wheat, but only 10 million acres of cotton. So many products, both food and industrial, come from these, but the acreage needed from each is so disparate that crop rotation is often problematic. Further complicating it is that each crop grows best in a specific climate zone and soil. It's really, really hard to find two or more crops that are both in equal demand and that will grow well on any given farm's ecology.

Three of these top five crops are mostly genetically engineered varieties. But as we can see, this has nothing to do with the problems of monoculture or the farmer's ability to rotate.

GMO crops contain genes from jellyfish and other animals.

False. There have never been any GMO crops brought to market that contained any animal genes. But it's not necessarily for lack of trying. In many parts of the world, crops can freeze and get destroyed. So one thing researchers have tried is to give them some genes that confer antifreeze abilities in the winter flounder, a fish that can survive sub-freezing temperature. These genes express a protein (found in many plants, animals, fungi, and bacteria) that binds to small ice crystals, preventing them from becoming larger ice crystals that can damage cells. Although it would be great if we could give fruit and vegetable orchards this same ability, so far it hasn't worked. This is why genetic engineers are always going to be busy: for every one project that succeeds, a hundred fail.

More herbicides are sprayed on GMO crops.

Mixture of true and false. It is probably generally true for one of the two dominant GMO crops on the market, those typically described as "Roundup Ready", that are resistant to glyphosate (GLY-fo-sate), the active ingredient in Roundup. Glyphosate's patent is expired, so it's now widely available and inexpensive. It affects the plant systemically, inhibiting the production of an enzyme needed for the synthesis of certain amino acids. Ideally, you can spray your entire field liberally with glyphosate, and only your Roundup Ready crops will remain. No weeds at all. Glyphosate is only 1/25th as toxic to humans as caffeine; so such agricultural usage is harmless, according to an EPA study that predicted no ill effects from a lifetime of eating unwashed, heavily glyphosate contaminated crops. Humans aren't plants and so it doesn't affect us the same way.

But evolution eventually finds a way, and weeds that have naturally evolved to be Roundup Ready have started to appear. It will probably always be an arms race between the farmers and the weeds. But no matter what technology is used to kill weeds, GMO or conventional, weeds will continue to evolve and adapt, so this is not a problem that's specific to GMO crops.

So the answer is true for Roundup Ready GMO crops: they are more likely to have been sprayed with glyphosate. But for GMO crops that have been designed for purposes other than resistance to glyphosate, there is no reason they would have been exposed to more herbicides than their non-GMO counterparts.

More pesticides are used on GMO crops.

False. Some GMO crops are designed for insect resistance, and so far less (and often no) pesticides are used on them at all. But for GMO crops with different traits, then again, they have probably been exposed to just as many pesticides as non-GMO counterparts.

The main type of insect resistance in GMO crops is the incorporation of a gene that allows them to express a certain protein that is toxic to certain of the most pesky shoot-boring insects. This protein is from the soil bacterium Bacillus thuringiensis, from where we get the name Bt Corn and so on. Bt occurs naturally in the soil, and it's the main active ingredient used in organic pesticides. So with GMO we simply cut one step out of the process; rather than spraying fields with Bt, we put it right into the crop itself.

But again, evolution rears its ugly head. Shoot-boring insects that are resistant to Bt have been appearing for as long as the bacterium has been in the soil, which predates GMO technology, and even predates the use of organic pesticides. Adaptive insects always have been a problem and always will. It is a problem that has nothing to do with GMOs. So for a related claim:

Bt GMO crops harm good insects as well.

False. It's the Bacillus thurengiensis that kills some desirable insects, like monarch butterflies, but it has nothing to do with whether they were sprayed with organic Bt pesticide or whether they nibbled on a Bt GMO crop. But so far, it hasn't been proven that butterfly larvae can get a harmful dose just from nibbling on the crops.

GMO crops have "terminator genes" making them sterile so farmers can't replant next season with the seeds from this season.

False. The patents for terminator genes have all been secured by companies like Monsanto who have pledged never to put them into commercial crops, and as a result, there has never been a GMO seed on the market with a terminator gene. It's also a national security issue; if some unforeseen natural or manmade disaster shuts down the infrastructure, food will be at a premium and neither the nation nor the world can afford the risk of having no crops available next season.

But more significantly, the underlying assumption that farmers would otherwise be reusing each season's seeds is false. Although most crops produce seeds that can be replanted for the next generation, trying to harvest these seeds is both impractical for most farms, and impossible for many commercial crops. It's possible with cotton and soy, but it's really labor intensive to try to collect seeds and you end up with a bad mixture that contains a lot of weed seeds and seeds of poor quality. It's much easier and cheaper for most farms to simply buy new stocks of seeds each year, and yields better quality crops. Corn is another matter. Most corn is a hybrid of two species, and doesn't produce usable seeds. All of these farming challenges have always been the case, and have nothing at all to do with GMOs.

Labeling of GMO foods protects consumers.

False. It doesn't protect them; it misinforms them by suggesting that some food is safer than others. Oft-repeated claims that GMO foods are inadequately tested are simply false; both the USDA and the FDA require exhaustive safety testing, as they do on all new foods. In the twenty years that GMO foods have been commercially available, there has been not a single observable consequence to anyone's health.

The only cogent suggestion that's been put forth is that getting crops to express a new protein is actually a plausible mechanism to provoke an allergic response. It just hasn't happened yet, nor do we expect it to. The largest research review to date examined 770 studies of health effects from GMO foods on either humans or animals, and found not a single example.

Eating transgenic food alters your genes and gives you a third eye.

True. This is why you see so many three-eyed people walking and flying around, and transmuting themselves through walls.

Obviously I'm being tongue-in-cheek here. The actual answer is false. When you eat food, your body does not incorporate the genes of what you eat into your own DNA. That's incredibly irrelevant to how the digestive system works. Genes that get digested are broken down into their constituent nucleotides by your digestive system. For those that pass through your tract without being digested, no mechanism exists for some type of complex gene-splicing to take place that would overtake your body. It made for fun science fiction in John Carpenter's The Thing, but it's not the reality of how digestion works.

So eat up. Enjoy your sweet corn, rejoice that probably very little or no herbicides or pesticides had to be used on it, and don't worry about growing a third eye.

Correction: An earlier version of this wrongly said amino acids where nucleotides was meant. —BD

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "GMO Facts and Fiction." Skeptoid Podcast. Skeptoid Media, 17 Feb 2015. Web. 12 Jul 2024. <>


References & Further Reading

Borel, B. "Core Truths." Popular Science. 1 Jul. 2014, Volume 285, Number 1: 56-59.

Charles, D. "Top Five Myths Of Genetically Modified Seeds, Busted." The Salt. National Public Radio, 18 Oct. 2012. Web. 2 Aug. 2014. <>

Editors. "Genetic Engineering Companies." Resources. Biology Fortified, 2 Jul. 2014. Web. 2 Aug. 2014. <>

EPA. "Major Crops Grown in the United States." Ag 101. U.S. Environmental Protection Agency, 11 Apr. 2013. Web. 2 Aug. 2014. <>

Harmon, A. "A Race to Save the Orange by Altering Its DNA." The New York Times. 28 Jul. 2013, Volume 162, Number 56,211: 1, 16-17.

Lallanilla, M. "GMOs: Facts About Genetically Modified Food." Live Science. Purch, 1 Nov. 2013. Web. 2 Aug. 2014. <>

Nicolia, A., Manzo, A., Veronesi, F., Rosellini, D. "An overview of the last 10 years of genetically engineered crop safety research." Critical Reviews in Biotechnology. 13 Sep. 2013, Volume 34, Number 1: 77-88.

Tripathi, S., Suzuki, J., Ferreira, S. "Papaya ringspot virus-P: Characteristics, pathogenicity, sequence variability and control." Molecular Plant Pathology. 20 Feb. 2008, Volume 9, Number 3: 269-280.


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