photo: Emily Mills | flickr | cc
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Like anything relating to GMOs, Neil deGrasse Tyson’s recent off the cuff remarks on GMOs and his exhortation to ‘chill out’ was met with competing choruses of cheers and jeers. I watched the reaction unfurl on his Facebook page (here and here) and on Chris Mooney’s posts in Mother Jones (here and here). These were interesting vantage points for related reasons. Chris Mooney writes about the politics of science and is particularly interested in how political loyalties tend to scramble our brains when it comes to picking and choosing which science we choose to accept (or even understand). Neil deGrasse Tyson is a great champion of the scientific method. So it was especially embarrassing and disconcerting to see their corresponding readers and fans parade through to lodge their disagreement with Tyson’s remarks based on a number of common and easily debunked misconceptions and fallacies.
Below I will give examples of the comments that were most emblematic. First, let’s look at what Tyson said.
In the video, all he really does is point out that we’ve been genetically modifying plants and animals through artificial selection to suit our needs for over 10,000 years and the fact that we can do it more precisely in a lab shouldn’t be any cause for concern. (So chill out.)
In his follow ups on Facebook, he broke out some issues that are of a political nature and told people that if they were concerned about patents or pesticides, etc; then focus on patent or pesticide, etc. All of which makes perfect sense.
But many weren’t having it.
The standard response was something along the lines of, “I love Neil, but I disagree with him on GMOs because [insert common misconception here].”
1. “I can’t believe that Neil is saying that GMOs and traditional breeding is the same. I don’t want to eat a tomato that has fish DNA. Breeding in a laboratory is not the same as breeding that happens in nature over hundreds of years.”
There are a number of problems with this. The first of which is that he didn’t say that using recombinant DNA breeding methods were the same at traditional breeding methods, he said that since we have been manipulating the genetics of our food for 10,000 he didn’t see any reason for getting worked up about the fact that we are doing in laboratories now.
Next up, let me point out that tomatoes and fish share around 60% of their DNA already, so it’s too late to avoid that mashup. Nature already put the chocolate in the peanut butter and the peanut butter in the chocolate. The question is, why would one more gene out of thousands be the deal breaker? Would you eat grapes with human DNA? Too late. Humans share around 25% of our DNA with grapes. We share 50% of our DNA with a banana. It doesn’t matter where the DNA comes from, it’s just the basic building blocks. It matters what it does.
While sentiment also stems from a lack of understanding of genetics, there are also some naive assumptions about breeding not considered genetic engineering. I’ve written before about just how specific and technically sophisticated contemporary plant breeding has become. Traditional breeders are going after traits which are just as specific as the traits sought by breeders using genetic engineering. This is something that few people are aware of. Nor do they realize just how sophisticated current methods are.
Consider marker assisted breeding:
[F]ruit and vegetable breeders at both universities and private companies have been turning to an alternative way of modifying the food we eat: a sophisticated approach known as marker-assisted breeding that marries traditional plant breeding with rapidly improving tools for isolating and examining alleles and other sequences of DNA that serve as “markers” for specific traits. Although these tools are not brand-new, they are becoming faster, cheaper and more useful all the time. “The impact of genomics on plant breeding is almost beyond my comprehension,” says Shelley Jansky, a potato breeder who works for both the U.S. Department of Agriculture (USDA) and the University of Wisconsin–Madison. “To give an example: I had a grad student here five years ago who spent three years trying to identify DNA sequences associated with disease resistance. After hundreds of hours in the lab he ended up with 18 genetic markers. Now I have grad students who can get 8,000 markers for each of 200 individual plants within a matter of weeks. Progress has been exponential in last five years.”
[see also: Backcrossing]
Meanwhile, to avoid the regulations that bog down development of genetically engineered crops, a company like BASF is using the Atomic Age method of radiation mutagenesis breeding to develop crops.
Mutation breeding, after booming in the 1950s with the dawn of the Nuclear Age, is still used by seed developers from BASF SE to Dupont Co. to create crops for markets that reject genetic engineering. Regulators don’t demand proof that new varieties are harmless. The U.S. National Academies of Science warned in 1989 and again in 2004 that regulating genetically modified crops while giving a pass to products of mutation breeding isn’t scientifically justified.
“The NAS hits the nail on the head and I don’t think that any plant- or crop-scientist will disagree,” said Kevin M. Folta, a molecular geneticist and interim chairman of the horticultural sciences department at the University of Florida. “Mutation breeding is absolutely the least predictable.”
That isn’t to say that mutation breeding is particularly dangerous. If you’ve ever had a Rio Star Grapefruit or Calrose rice, you’ve eaten the fruits of mutagenic breeding. It’s just to point out that, today almost no breeding happens that doesn’t involve a laboratory and it’s been a long time since it resembled anything that happens in nature. But that was Tyson’s point. Even the breeding that we did 10,000 years ago wouldn’t have happened in nature. The crops we’ve bred would not have happened in ‘nature’ and they wouldn’t survive in ‘nature’ if we turned them loose. So Tyson’s statement makes a lot more sense if you understand genetics a little better and if you understand breeding a little better.
2. “I don’t want to eat food that makes insects stomachs explode! / I don’t want to eat food that’s been bred to withstand being drenched in toxic herbicides”
This was the second most common reaction to Tyson’s comments, but it may be the most common misconception out there. Let’s try to reconnect it with reality a little bit. There are currently two major traits that GE crops have been bred for.
The second most common trait is the Bt trait. This has been bred mostly into corn and cotton, but is making it’s way into other crops as well. Corn borers and bollworms are two major pests for corn and cotton. These pests have been managed for decades with the organic pesticide Bt which is a soil bacteria which is poisonous to these insects. It’s important to understand the ‘mode of action’ through which Bt kills these insects. In fact, it’s important to understand the concept from toxicology of ‘mode of action’.
Mode of action is the way that a substance acts as a toxin. Most so-called poisons aren’t poisonous in a vague general way. They do something specific to their ‘targets’. The more specific, the better, because something can be very toxic to one organism and harmless to another.
Bt (Bacillus thuringiensis) produces a protein (Cry protein) that when eaten by these bugs is activated by the alkaline environment of their digestive system and binds to a receptor there, paralyzing the digestive system.
The reason this insecticide is so safe is because the mode of action is specific to the target pests. Humans and other mammals have acidic digestive systems, so the protein is broken down in our digestive systems and we don’t have a receptor for it to bind to and paralyze our digestive system. It’s just another protein.
Breeding corn or cotton to express the Cry proteins has an added advantage for the environment. Not only is it harmless to critters without the necessary receptor, but it only kills bugs that eat the plant and leaves other bugs alone, while spraying with Bt can kill some bugs that don’t pose a threat to the crop.
The adoption of the Bt trait in corn and cotton has meant a massive reduction in the amount of soil applied insecticides applied by conventional farmers. (Yes, there is some resistance to Bt developing in insects in some parts of the country and farmers are falling back on some of those insecticides. This is a standard pest management issue and its not clear why this should be seen as making the case against using these crops in the first place.)
Let’s look at two charts the first taken from the journal Science based on USDA data.
The second drawn from a study that looked at insecticide traces found in air samples.
Raise your hand if you want to go back to the profile of insecticide use from 1995, the year before the first genetically engineered corn hit the market.
By the way, lots of plant produce their own insecticides. The idea for Bt crops came from nature. In fact, 99.99% of pesticide ‘residues’ in your diet were produced by the plants themselves, naturally.
‘drenching crops in toxic herbicides‘.
What we are talking about here is herbicide resistant crops, most notably Monsanto’s RoundUp Ready crops. These have been bred so that they don’t die when the herbicide RoundUp (glyphosate) is applied to the fields to kill weeds. The reason that RoundUp was chosen is that it is much more effective than other herbicides while being relatively non-toxic and easy on the environment IN COMPARISON to other herbicides. In fact, for acute toxicity, RoundUp is less toxic to mammals than table salt or caffeine. Again, this has to do with ‘mode of action’. The reason it is incredibly effective as an herbicide is also the reason it isn’t a poison to mammals.
Glyphosate works by inhibiting a metabolic pathway that only plants and bacteria have. For critters that don’t have the shikimate pathway, it is just another salt with the normal toxicity of salt (less than sodium chloride). If you are a plant that relies the shikimate pathway for converting light into energy, it’s literally ‘lights out’.
So while use of glyphosate is up, use of other more problematic herbicides is down. It works so well that it allowed many farmers to adopt what is known as conservation tillage. Tillage is an important tool for controlling weeds. Prior to planting the farmer tills the soil to interrupt weeds which would cause problems during the growing season. While this may seem like a good way of avoiding using herbicides, it releases lots of carbon into the atmosphere, uses plenty of tractor fuel and cause problems with erosion and soil structure. The judicious use of a low environmental impact herbicide like glyphosate is often the environmentally friendlier strategy.
Consider this chart taken from the same study showing trace amounts of herbicides in air samples. Again, a show of hands if you’d like to return to the 1995 herbicide profile (keeping in mind that the category of ‘other herbicides’ that have fallen out of favor, nearly universally had a higher environmental impact).
We should address what we mean when we say “drenched in herbicides”. Luck for us, Kevin Folta recently did the math.
An acre is 4047 square (meters). That means 83 milligrams per square meter. My 7th grade science teacher Mr. Herzing said, “A milligram is about the weight of an insect wing.” Wow, that seems like not much! But how much soybeans does that get ya? Soybean yields in 2013 were 43.3 bu/acre and a bushel weighs 60 lbs, so that’s about 2598 lbs/acre, or 1180 kg/acre. To make it relatable to herbicide used, we need to get it down to square meters. That’s 291 g soybeans per square meter. So 83 mg of active ingredient is needed to produce 291 g (0.640 lbs) soybeans. Of course these numbers assume one application, which is likely not the case, but it still is a tiny amount.
Before we move on, I’m sure that some of our readers are starting to rumble about so-called ‘superweeds’. Superweeds is a sensationalized term for weeds that develop resistance to the strategies meant to control them. What you need to understand is the same thing with Bt resistant insects. If the RoundUp Ready strategy is over used, you end up back close to square one, except you’ve gotten a decade of reduced environmental impacts and now you have to change up your game a bit, using some of the tools you would have used if you didn’t have RR crops.
Herbicide resistance is hardly unique to glyphosate. In fact it’s a much bigger problem for other categories of herbicide, but you never hear about that because people are just looking for something to write about and anything with GMOs makes for great reading (I get the irony here.)
You want talk about ‘superweeds’ and glyphosate and the role of GE crops, let’s talk about ALS inhibitors, trianzines and ACCase inhibitors first and then you can tell me how GE crops ‘create superweeds’. Look at those steep curves where each of those other herbicides was out-evolved by weeds, and then look at the rate for glycines and consider the massive amount of acreage they are used on. Glyphosate is actually pretty miraculous in its ability to thwart weeds from developing resistance. I’m sorry, but the ‘GE crops create superweeds’ story doesn’t hold water. What causes resistance is over-reliance on a single strategy, that isn’t specific to GE crops as the cases of those other herbicides with much greater numbers of resistant weeds demonstrates.
3. “GMOs may be safe but I have a problem with patenting food and companies that sue farmers if their neighbor’s pollen blows into their field.”
Let’s start with the second part first.
This is simply an urban myth. Monsanto does not sue farmers for accidental pollination. Even if they did, it would not hold up in court, the case law is very clear on that point. Farmers who knowingly violate the end user agreement covering those seeds are the ones who are taken to court. Don’t wish to end up in court? Don’t violate the agreement. (Feel free to try to find an example that holds up to a fact check and make me look foolish) This urban legend has its roots in the story of Percy Schmeiser, a Canadian canola farmer who claimed to have noticed that some of his canola was RoundUp Ready from accidental cross pollination and decided that he now had a way to use what would normally be premium seeds for next to free if he started saving them. The problem with Mr. Schmeiser’s story is that he was A.) obviously trying to pull a fast one, and B.) there was too much RoundUp Ready canola for it to have been from accidental pollination. (The court’s ruling can be found here..)
On to patents and plants.
Here is what Tyson said about patents and crops.
In a free market capitalist society, which we have all “bought” into here in America, if somebody invents something that has market value, they ought to be able to make as much money as they can selling it, provided they do not infringe the rights of others. I see no reason why food should not be included in this concept.
It’s curious that people think that plant breeders should not have the same protections as other inventors and innovators. In support of the Plant Patent Act of 1930, Thomas Edison testified before Congress in support of the legislation and said that “This [bill] will, I feel sure, give us many Burbanks.” refering to Luther Burbank the great plant breeder of the late 19th and early 20th centuries.
The Plant Patent Act of 1930 didn’t cover sexually propagated plants so corn wasn’t covered until the Plant Variety Protection Act of 1970, but around 1930 hybrids became the norm for corn meaning farmers had a reason to buy new seed every year and breeders could make money by giving them something better every year. Consider:
Corn yields have increased by a factor of six since breeders had a real incentive to create better seeds. Going back to the seeds and yields that we had before 1930 would be an economic and ecologic disaster. Just like in software, there is room for open source projects, and we do need to restore public funding for breeding programs, as with any capital intensive innovation, patents are valuable to make sure that innovation still happens.
There were other issues that people raised, but most of them were equally off base. We’ll be exploring those and others in a project that we are about to kick off next week. Stay tuned.
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1. Be awesome to each other. Use the Principle of Charity
2. No name calling. (calling someone any version of shill or a kook will get you bounced without warning.)
3. Don't get personal, stick to the issues and the evidence.
4. Be prepared to back up your claims. Expect to get fact checked.
5. Stay on topic. If you want talk about something else, use the search function and find a thread that interests you. (Hint: Labeling is not the topic of every post related to GMOs. It IS the topic of this post.)
6. Don't argue with the moderator about moderation.
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