Genetically Modified Organisms
For many, many years I have been passionate about food and about science (not necessarily in that order). Since probably the 1950s, when processed food and thus “food science,” was invented, these two subjects have become intertwined and interconnected, and at the same time, so much more complicated. I have long been pondering questions like
- How do we know what food is best for our health?
- How is our food produced and processed, and how does that make it more (or less) delicious or nutritious?
- When at the grocery store, how do we decide what is the best, healthiest, food to prepare that also nourishes farmers (in our country and beyond), supports farmworkers, and treats our planet well?
As one part of the answers to these questions, let’s delve right into a science/food topic that is especially close to my scientific heart, Genetically Modified Organisms, or GMOs…
GMOs – What Are they and does it really matter?
A GMO (genetically modified organism, also known as Genetically Engineered, GE) is a plant or animal that has had a gene inserted in its genome in order to make it better, (faster, stronger)… that is to say more nutritious and easier to grow effectively. The added gene could be from another variety of the same plant or animal or it could be from a completely different species. It could even be a plant gene inserted into an animal, or an animal gene inserted into a plant. It’s like traditional breeding but on steroids. Since their adoption in 1996, GMO crops have saturated the US and beyond.
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| By 2012, 88 percent of corn and 94 percent of soy grown in the United States were genetically modified, according to the US Department of Agriculture.
GMOs are often lumped together under the same heading, as if every GMO were the same and had the same positives and negatives. But in truth, there are different sorts of genetic modification. |
I’ll divide my discussion of GMOs by the broad categories pesticide-resistant, or Roundup Ready GMOs, insect-resistant GMOs, andother (Out of This World) GMOs.
Pesticide-Resistant (Roundup Ready) GMOs
What if your crops didn’t die when exposed to a broad pesticide, one that pretty much kills all other plants (all the weeds)? Roundup Ready GMOs do exactly that. The DNA of Roundup Ready plants include pieces from a soil bacteria that is naturally immune to the herbicide glyphosate (Roundup TM). The Roundup Ready plants can tolerate glyphosate and weeds cannot. Glyphosate has been a remarkably effective herbicide advertised by its makers to be relatively innocuous to humans (see the “Take a closer look” Link below for the latest news on this front). Non GMO crops sprayed with Roundup would die along with the weeds, but inserting the soil bacteria gene into the crop plants allows farmers to use Roundup to kill any weeds without harming the crop plants themselves. The makers of the GM crops promised farmers that by using Roundup Ready GM seeds, they would be able to spray low doses of an effective but harmless herbicide, control weeds completely and increase their productivity tremendously. This sounds like a boon to farmers, right? Unfortunately, it’s just not that simple.
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| Many have argued that foods sprayed with any amounts of a broad poison such as Roundup cannot be good for people to eat, though there were no studies to prove this.
Europe chose to ban most Roundup Ready GMOs until they were proven safe, while the US chose to approve the crops until they were proven unsafe. Recently, Roundup was determined to be a probable carcinogen. See this summary from PBS (or the original Lancet article here). |
Negative (though not unexpected!) Side Effects: Unfortunately, there have been some not so great consequences to this approach, even beyond the idea that adding a herbicide to food crops, even one as “mild and effective” as Roundup, is a great idea.
The long term effects of continuously spraying Roundup have, been studied, and are not pretty. Not surprisingly, the weeds evolve, with those small amounts mutated to be naturally resistant to Roundup surviving applications of Roundup and reproducing. Over time and as more of the weeds demonstrate resistance to Roundup, more Roundup is needed to control these weeds.
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| See this peer-reviewed article about “superweeds,” weeds that have evolved to be resistant to Roundup. Resistant superweeds mean more pesticides are necessary to control them. So much for a magic bullet. |
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| This is exactly the situation that is being observed with antibiotic overuse leading to antibiotic resistant bacteria, by the way. |
So Roundup Ready GMOs have some pretty strong negatives. Roundup itself does not appear to be as safe as claimed (no surprise there, perhaps) and the repeated application of even low doses of Roundup to food crops leads to the evolution of superweeds that are resistant to the pesticide, meaning that more and more poison needs to be used to control the weeds.
To add to the mix, there is another positive outcome of Roundup Ready GMOs, in the form of “no tillage farming.”
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| Using Roundup on crops allowed the adoption of no tillage farming, where the top layer of soil is left in place year after year, and seeds are pushed into the ground.
Tilling is usually required to control weeds, since chopping weeds up and plowing them under effectively destroys them. But tilling is labor intensive (think of images of farmers of old turning over the soil with teams of oxen, for example) and machine intensive (since farmers in the US use tractors, which require fuel to run, rather than oxen). If the weeds are controlled by Roundup, tilling isn’t needed. Leaving the old plants, and disturbing the soil minimally, means that the soil is less prone to erosion, retains more water and releases less carbon. |
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| The characteristics of no-till-farming are good for crops, good for the planet, and good for farmers. But are these benefits enough to outweigh the necessity of pesticides to control weeds? See this article from US News and World Report for more details. |
Conclusion: It seems there is sufficient reason to condemn this variety of GM crops: Roundup Ready GMOs, by far the largest and most well-known kind of genetically modified organisms, haven’t fulfilled their initially promised benefits, and have demonstrated, clear negatives.
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| Need more convincing? From the American Bar Association (look under the section on Health Concerns) and the New York Times. |
It’s no surprise that there are a lot of strong feelings against Roundup Ready GMOs. But that’s not the only variety of genetic modifications, or the end of the story! Next, let’s consider another variety of GM crops – those plants modified to be insect resistant.
Insect-Resistant GMOs
Insects are the bane of a farmer’s existence. They are happy to munch on the crops that the farmer is growing for himself, and damage from hungry insects can be catastrophic. With this in mind, Monsanto developed a genetically modified corn plant by inserting a protein found in the bacterium acillus thuringiensis that is poisonous to the European core borer, the most damaging pest (it interferes with their gut functions and kills their larvae. The bacteria, sprayed on crops, have been used for many years in organic farming). In 1996 the first corn plant modified to include the insect-killing protein Bt, was approved.
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| For more detail about how Bt works against pests, see this article from the University of California San Diego.
Or this excellent, comprehensive page from the University of Minnesota on Bt corn and how the bacterium protein works. |
The immediate benefits of insect-resistant crops are more straightforward than those of Roundup Ready crops. The crops include a protein that is well studied and not at all harmful to humans (the protein only interacts with the larvae of the corn borer and has no impact on humans; it is not a broad poison like Roundup). With careful crop management (allowing a buffer zone of unmodified corn, which allows some non-mutated insects to survive) the insects are not supposed to develop a resistance to the protein; the equivalent of “superweeds” to Roundup-Ready crops. Because the corn plants produce their own Bt toxin, the protein doesn’t degrade in the sun, and it is uniformly and continually “applied” (it doesn’t have to be sprayed on using carbon gobbling tractors). As promised by the seed companies, insect resistant crops virtually eliminate the use of most chemical insecticides. Overall, the development of insect-resistant crops has been a profound win for farmers, for consumers and for the environment.
A succinct article on the success of Bt corn can be found on Grist here (“In the Insecticide Wars, GMOs Have So Far Been a Force For Good”).
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| It seems that insects are developing a resistance to the Bt gene, in some cases (see this page from the EPA’s website about what is happening and what steps farmers can take to help). It’s not insurmountable, but will require more thoughtful farming practices to keep insects from becoming resistant. Especially since Bt corn does not have the intrinsic health negatives as Roundup Ready GMOs, this is not a deal-breaker. |
Adding Fish Genes to Tomatoes
(i.e. modifying plants for traits other than resistance)
It makes sense that modifying plants to withstand the application of chemical pesticides is not such a great idea (bad Roundup Ready!). But it seems that modifying plants to resist insects on their own works, with conditions (yay! for Bt corn). GMOs aren’t all bad. That’s a start. It remains to be seen if we can manage insect-resistant GMOs effectively enough so resistant insects do not become a problem.
How about some other possibilities for genetic modification? There are so many possibilities, it can be mind boggling.
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| Read this Mother Jones article about some genetic modifications that make dairy cows healthier and happier… The genes involved are all cow genes. Maybe that make this kind of modification more palatable? |
This broad class of GMOs is more varied, and the science and science ethics are more nuanced than that of either Roundup Ready or insect resistant crops. If you are prone to philosophical musings, you may wonder if it is “right” to be messing with nature in this way. That is a question for you to decide for yourself. I personally think it is a pretty cool thing. You might think it is a little too much like playing God for your taste.
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Personally, I think the coolest GMOs are the plants (or animals) that have been given genes from widely different species to give them particular traits. Examples include:
Here’s an exciting recent development: Scientists at the University of Illinois, funded by the Bill and Melinda Gates Foundation, have created a GMP tobacco plant that photosynthesizes 20% more efficiently. Wow! Check out the New York Times article here. |
Speaking of playing God…
Next up… Why Vaccinate??