New Video: “Are GMOs Natural?”

A while back I posted a picture on twitter of a process called the “floral dip” which is science-speak for dipping a whole dang plant in a bath of microbes to make a GMO.

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Someone asked in the comments if there was an explanation of this process anywhere. I couldn’t find one, so I decided to make a video. Two years later, here is the finished product.

In this video, which I produced as a member of the UC Davis science communication and outreach group “Science Says“, I explain what causes those big tumors we sometimes see on tree trunks or plant roots, and how scientists have borrowed techniques from this natural phenomenon to add genes to plants for agriculture and research purposes. It is meant to be an educational video that cuts through the “are GMOs good or bad” debate and simply explains how they’re made. Please watch it and share it widely!

GMO labeling compromise: the good, the bad, and the ugly

Republicans and democrats in the Senate have reached a compromise on federal GMO labeling. The push to “just label it” has drawn on for years, but it’s not that simple. GMOs are tough to even define, and the FDA does not have the jurisdiction to mandate a label that is not relevant to health and safety. Many insist that consumers simply have the “right to know”, but without any grounds for safety concerns, this is a compelled speech argument. Nonetheless, to prevent a patchwork of messy state laws like Vermont’s, a compromise was necessary. Compromise is good, but it can be a little awkward.

The Good

  1. Consumer empowerment. Foods containing GE ingredients will now be identifiable by text on the label or via a QR code or website on the package. Many pro-labeling activists complain about the inconvenience of having to use a smartphone to label check. But if you wanted to know how cosmetics, clothes, electronics, cars, or anything else was made you’d have to go tour a factory. Consumers have never had so much information at their fingertips.
  2. No skull and cross bones. While companies are required to make information about GE ingredients available, there doesn’t have to be a label right on the package. Labels that do not communicate legitimate health and safety concerns can elicit unnecessary alarm or create “health halos” around foods that are otherwise not nutritious.
  3. Potential for more relevant information. Imagine a future where you can scan a QR code and learn where, how, and when a food item was produced. Food journalists have repeatedly shown that puff terms like organic, locally/sustainably grown, and free range are mostly smoke and mirrors. What if we could scan a QR code and learn the farm address, harvest date, and sustainability metrics? Obviously this would require quite the paper trail, but with some of that infrastructure already in place, the path forward is clearer.

The Bad

  1. Arbitrary inclusions/exemptions. Under this bill, meat/dairy from animals fed genetically engineered feed are exempt. This makes sense as there is no measurable difference between animals fed GE and non-GE diets. However, processed foods containing byproducts from GE crops such as canola oil, corn syrup, and beet sugar are not exempt. These ingredients are chemically identical and completely indistinguishable from their non-GE sourced counterparts. This inconsistency has no logical basis.
  2. Pressure to go GMO free. Due to real or presumed consumer opposition, some companies may opt to source non-GE ingredients. Hershey has already promised to do so, and the prospect is alarming. The majority of sugar in the United States comes from domestically grown GE sugar beets, which allow farmers to decrease the volume, number of applications, and toxicity of pesticides they use. Hershey has already asked for tariff lifts on cane sugar imports to meet their demand. This is just one example of the possible economic and environmental costs that could result from a sudden demand for GE free goods.

The Ugly

  1. Would you like a side of bureaucracy with that? Opponents of GMO labeling claim label changes will increase the cost to produce goods translating to pricier groceries. Proponents of labeling insist that companies change labels all the time with no fluctuation in retail price, so the cost is clearly not substantial. Both are correct. Labeling will likely increase cost, but not because of the price for reprinting the label itself. The cost will come in the added layers of bureaucracy required to track ingredients, possibly change ingredient sourcing, or even build separate manufacturing facilities. Not to mention the inevitable legal fees when a mistake is made.
  2. Unequal access to information. Not everybody caries a smart phone or knows how to use a QR code. On a fundamental basis inequality in access to information on the basis of socioeconomic status or tech savvy is not cool. That said, a QR code stating whether a product includes GE ingredients doesn’t actually provide consumers with any necessary information. It says nothing about the safety, nutrition, or environmental sustainability of a food product. At the end of the day, if we really want to know how food is grown and produced, we’ll still have to look to farmers, scientists, and food industry professionals, not labels.

Okay, so what the heck are “omics”?

In the National Academy of Science’s genetically engineered crop study report released a few days ago, they proposed a new regulatory framework for analyzing the safety of any crop variety that relies on a technology called “omics”? So what in the world is an omic and how is it useful?

There are many different types of “omics”. It all started with GENomics which involves figuring out and comparing the GENES between organisms. This has allowed scientists to identify different genetic “markers” associated with diseases and other traits. However, genomics are only part of the story. Just because a gene is present doesn’t mean it is active.

Active genes are used as a template to TRANSCRIBE molecular messengers called RNA. Analyses of the levels of RNA within an organism in a given tissue or in response to a certain stimulus are known as TRANSCRIPTomics, but it doesn’t stop there.

RNA transcripts serve as instructions that enable cells to build PROTEINS. Proteins are the real workhorses of the cell, and are largely responsible for an organism’s traits. Comparisons of the protein landscape in an organism are accomplished by PROTEomics.

But what about all the other cool stuff floating around in cells? Hormones, pigments, vitamins, ethanol? These molecules are assembled within cells and are called METABOLITES (and plants have way way way more of them than people: nicotine, caffeine, capsaicin…..). And guess what? Where there’s a molecule there’s an “omics”, so now we’ve got METABOLomics.

So omics includes the study of the genes, RNA, proteins, and metabolites in an organism (there are even more, but I won’t go there). Sound complicated? It gets worse. When scientists gather data for omics studies, they get it in pieces.

So you know the human genome project? It’s not like somebody scanned a human blood sample and printed out the entire genome. To put it into perspective, if the human genome was unravelled and blown up to the diameter of a strand of hair, that hair would be 30 miles long and form a wad the size of a volleyball.

The genome had to be sequences piece by piece (not particularly systematically) and then those pieces had to be reassembled. To put it into perspective, Dr. Keith Bradnom uses the following analogy: Take 100 identical jigsaw sets, mix all the pieces together, throw away 10% of the pieces, randomly mix in the contents of an unrelated puzzle, throw away the cover of the box, and assemble!

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Some scientists on twitter even called this analogy an over-simplification! As you can imagine, this takes not only a lot of brain power, but also a lot of computing power. Then once you finally get it assembled….


So that’s why the National Academy of Sciences said that we need to further develop these technologies. The idea is that we could compare the “omics” between new crop varieties and existing varieties and analyze any significant differences for potential safety concerns. As you can see, this is no small project, and that’s why they call it “big data”.

If you are a non-scientist, I hope you found this explanation helpful. If you are a scientist, particularly a computational scientist, please let me know in the comments if I’ve made any mistakes or am missing important details.

Editorial Summary of the National Academy of Science’s Consensus Report on Genetically Engineered Foods

This morning, the National Academy of Sciences (NAS) released a consensus report titled “Genetically Engineered (GE) Crops: Experiences & Prospects”. You can download the full 400 page report which includes a four page summary here. The public release of the report was accompanied by a webcast including a presentation of the report followed by a question and answer session. My notes on the webcast including screen shots of many of the slides are synthesized below. I apologize for any missing slides or points. None were omitted intentionally. As a scientist, I tended to focus my notes more on human health and the environment and less on social/economic points.

The NAS is a private, non-profit organization that “is charged with providing independent, objective advice to the nation on matters related to science and technology. Scientists are elected by their peers to membership in the NAS for outstanding contributions to research. “

Volunteers for the NAS committee to assemble the consensus report were vetted for potential conflicts of interest. The committee was composed of a very diverse range of scientists and experts from a variety of different topic areas ranging from entomology to science communication. The committee was initially divided, as there were many different views on the prospects and progress of genetically engineered crops. However, all members were required to back their claims with evidence as the discussion progressed, and they ultimately came to a consensus that best reflects the available data.


In analyzing the issue, the committee looked to two decades of scientific literature including nearly 1000 articles. They also listened to input from 80 diverse speakers, and reviewed over 700 public comments. These videos and other materials have all been archived and are publicly available. The study was sponsored by the New Venture Fund, the Gordon and Betty Moore Foundation, the Burroughs Wellcome Fund, the U.S. Department of Agriculture, and the National Academy of Sciences. The report had 26 diverse reviewers. The committee had to respond to each of their comments and defend their conclusions with evidence.

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methods 3

The first key message from the committee emphasized the increasing difficulty of differentiating crop improvement technologies that qualify as GE from those that do not (you can read my personal explanation of this issue here). The chair of the committee Dr. Fred Gould likened this to the invention of cell-phones, cameras, and lap-tops which were once all distinct technologies that now have overlapping functions.


For this reason, the committee contends that it is impossible to “make sweeping generalizations about the benefits and risks of GE crops”. For the report, they mainly focused on three of the most widely grown GE crops: corn, cotton, and soybeans. The report also focused on the two most commonly utilized traits: insect (BT crops) and herbicide (RoundUp-Ready crops) resistance.

The committee generally concluded that insect resistant crops result in increased yields due to fewer losses from pests. Planting of insect resistant crops also correlates with a decrease in the application of synthetic pesticides and an increase in biodiversity. However, improper management of insect-resistant crops can and has resulted in the evolution of resistant insects.

insect resistance

They also concluded that the planting of herbicide-resistant crops can lead to an increase in yield. Beyond yield, the technology is substantially useful to farmers for several reasons. Herbicide-resistant crops allow farmers to apply a single herbicide where they might before have used many at a time when it is optimally convenient, safe, and physiologically advantageous for their crops.


My screenshot of this slide did not turn out, so I looked it up in the archives

The committee also notes that weeds (like the insects) have evolved resistance to this herbicide creating a huge challenge for farmers who will need to change their management strategies. The committee also made a point to emphasize that comparisons of kilograms of herbicide use before and after herbicide-resistant crops were widely adopted is not meaningful unless the health and environmental impacts of those herbicides are also compared.

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The committee’s analysis of the environmental impact of GMOs, revealed some evidence of gene flow from GE crops into wild ecotypes, but only under experimental conditions. The committee in general found that there was no evidence of environmental problems caused by growing GE crops. There was also no direct connection between the use of herbicide-resistance crops and no-till practices as farmers had already begun to move away from tilling prior to the advent of GE crops.


In response to the question of whether or not GMO crops are contributing to yield increases, the committee contends that they are. They acknowledge that what’s good for one farmer is not good for another, but farmers in general are gaining from the technology.

yield rate

That said, as these graphs show, there is not a spike in yield increase following the advent of GE crops (indicated by the vertical purple line). This likely demonstrates that changes in management practices and genetics through conventional breeding and other crop genetic improvement methods are equally as important for increasing crop yield. New types of GE crops could potentially contribute to the rate of increase depending on the traits introduced and the socioeconomic/cultural/legal factors that influence the adoption of new GE crops.

yield 2

To assess the impacts of GE crops on human health, the committee analyzed over 200 existing studies, looked for changes in patterns of human health before and after the adoption of GE foods, and compared the overall health of people in the United States and Canada (where GE crops are widely grown) with the health of people in Europe (where they are not). The committee reported that many of the existing animal studies were not optimally designed.

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Reports of long-term health of livestock fed GE diets and studies comparing nutrient and chemical compositions of GE food were more reliable. From these, they did not find any reliable evidence linking GE foods to health concerns. They also did not find any differences in human health that correlated with the adoption of GE crops.

human health 2

Given the lack of legitimate health concerns associated with GE foods in general, the NAS proposed a new system for regulating future GE foods. The proposed regulatory approach would compare the “omics” (levels of various compounds including nucleic acids, proteins, and metabolites) of new crops with the same levels in existing varieties.

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New crops would then be categorized as Tier 1 if there are no differences or Tier 2 if there are differences that have no expected health or environmental effects. Tier 1 or 2 crops would not require any further testing. If the new crops have differences with potential for health or environmental effects or differences that cannot be interpreted, they would be classified as Tier 3 or Tier 4 respectively and would require further testing. Under this system, most new varieties would fall under the category of Tier 1 or Tier 2.


On the issue of labeling, the committee concluded that because there are no health effects associated with GE food, there is no justification for labeling them on the basis of food safety. There are, however, policy reasons for which labels might be instituted such as consumer autonomy. It is outside of the legal authority of the FDA to institute a label for policy/cultural reasons, so labels would need to be mandated at the congressional level.

Read what a handful of other academic scientists had to say about the report here.


So you heard GMOs are banned in Europe…

The lowdown: The European Union has approved the cultivation of one GMO and importation of many (with more on the horizon). The European Commission and European Academies Science Advisory Council, like other government and scientific associations around the world, supports the evidence-based conclusion that GMOs currently on the market are not any less safe than  their conventionally bred counterparts. Nonetheless, certain member states within the EU have elected to ban cultivation of EU-approved GMOs on political/cultural grounds.

The details: Headlines claiming that GMOs are banned in Europe abound. These are often accompanied by an assertion that the United States should follow suit. Does the EU know something the US does not? Where are these claims coming from?

In response to the question “why are GMOs banned in other countries,” Dr. Robert Paarlberg, Professor of Political Science at Wellesley College and Adjunct Professor of Public Policy at the Harvard Kennedy School, clarified:

Very few countries explicitly ‘ban’ GMOs. In most cases, governments have simply not yet ‘approved’ various GMO crops for cultivation, or for import, or for human consumption. The presumption that each separate GMO should require case-by-case and use-by-use approval, by national government regulatory committees, has greatly slowed down the uptake of the technology. In effect, GMO foods and crops are being regulated as strictly as medical drugs, even though there is no evidence that they carry more risks than conventional foods and crops (in the official opinion of the EU Research Directorate, for example). Critics of GMO crops have promoted highly precautionary regulatory systems as one way to slow down the spread of the technology, and in large parts of the developing world governments have not yet given any cultivation approvals at all

As has been previously noted, Europe is not a unified country, but a continent made up of separate countries, many of which participate as member states in the coalitional European Union. The  EU as a whole has established directives regarding the import and cultivation of GMOs, and, like the US, requires pre-market safety testing and post-market environmental monitoring of GMOs. The EU has only authorized one crop for cultivation, pest-resistant Bt corn (Mon-810), however 58 GMOs have been approved for import as food and feed, and 58 more are awaiting regulatory approval. 17 of these have received a positive European Food Safety Authority (EFSA) assessment, and one is inconclusive. Applications for cultivation of 8 additional GMOs (including one renewal of Mon-810) are pending, and 4 have received a positive EFSA opinion.  Furthermore, the EU relies heavily on external sources for soymeal, and imports more than 60% of plant protein needs. 90% of these imports originate from countries where GE soybeans cover 90% of total soybean acreage.

Within the EU, member states can choose to ban the cultivation of GMOs that have been approved by the European Commission. Previously, a member state could elect to ban cultivation of approved GMOs only “if they had new evidence that the organism concerned constitutes a risk to human health or the environment or in the case of an emergency”. No such evidence has ever been presented. In response to a series of legal battles, the EU revised its guidelines to grant member states more freedom over decisions to ban GMO cultivation. Under the new (2015) directive:

a Member State may prohibit or restrict the cultivation of the crop based on grounds related amongst others to environmental or agricultural policy objectives, or other compelling grounds such as town and country-planning, land use, socio-economic impacts, co-existence and public policy.

Reluctance of some European countries to cultivate GMOs is often cited as evidence that European scientists and authorities are uncertain of their safety:

Washington wants Europe to ease restrictions on imports of these foods, commonly known as GMOs for genetically modified organisms, but the EU is skeptical they are safe.

However, according to an extensive European Commission Report on EU-funded GMO research:

The main conclusion to be drawn from the efforts of more than 130 research projects, covering a period of more than 25 years of research, and involving more than 500 independent research groups, is that biotechnology, and in particular GMOs, are not per se more risky than e.g. conventional plant breeding technologies.

Within the report, Marc Van Montague Chairman of the Institute of Plant Biotechnology for Developing Countries (IPBO) at Ghent University in Belgium goes on to say:

Now, after 25 years of field trials without evidence of harm, fears continue to trigger the Precautionary Principle. But Europeans need to abandon this knowingly one-sided stance and strike a balance between the advantages

Further, the European Academies Science Advisory Council has stated:

The scientific literature shows no compelling evidence to associate such crops, now cultivated worldwide for more than 15 years, with risks to the environment or with safety hazards for food and animal feed greater than might be expected from conventionally bred varieties of the same crop.

Despite approval of GMOs, much of the food in EU member-state grocery stores is GMO-free, because, according to the European Commission:

Many food business operators have made the choice of not placing GM food on the shelves. This may be linked to the labelling obligations of the GMO legal framework, as well as the availability of non-GM alternatives.


Here are a few other helpful resources on GMO regulation in the EU:

GMOs: EU decision-making process explained

Fact Sheet: Questions and Answers on EU’s policies on GMOs. April 22, 2015

A decade of EU-funded GMO research

European Academies Science Advisory Council: Planting the Future

A look at GMO policies in different nations. Layla Katiraee, July 6, 2015

Where are GMOs grown and banned? Genetic Literacy Project, Accessed April 27th, 2016


So you heard GMOs cause “superweeds”….

The low down: Superweed is a misleading term used to describe weeds that are resistant to an herbicide. It is conceptually possible that certain, herbicide-resistant GMOs could contribute to an increase in herbicide-resistant weeds; however, such concerns are not limited to GMOs, but are relevant for any crops used in conjunction with herbicides.

The details:  First of all, what is a superweed? According to the Weed Science Society of America (WSAA), there is “no science-based definition for superweed,” but the term is often used to describe herbicide-resistant weeds.  Just as overuse of one particular antibiotic promotes the spread of bacteria resistant to that antibiotic, overuse of an herbicide can result in herbicide-resistant weeds. According to Rick Boydston of the USDA-ARS:

Resistance is a natural phenomenon which occurs spontaneously in weed populations, but is only noticed when a selection pressure is applied to the weeds via herbicide application

Boydston further explains that herbicide resistant plants within a given population of weeds are rare:  “1 in 100,000 to 1 in 1,000,000”. Treating this population with an herbicide provides selective pressure, so that only the few resistant plants naturally present in the population go on to produce the next generation, thus passing on the resistance trait.

Weed scientists like Dr. Andrew Kniss find use of the term superweed to describe herbicide-resistance “exceptionally frustrating” because it “indicates that the weed is super in some way”. However, despite claims that “Some runaway weeds in the southern U.S. are said to be big enough to stop combines dead in their tracks,” herbicide-resistant weeds are not any bigger or nastier than their non-resistant counterparts.

Anti-GMO activist groups like Food Integrity Now call herbicide-resistance “a direct result of growing GM crops”. Where do these claims come from?

There are two ways that specifically herbicide-tolerant GMOs could hypothetically contribute to a rise in herbicide-resistant weeds. It is important to note that not all GMOs are herbicide tolerant. The following points apply only to crops that have been genetically modified to tolerate the herbicide glyphosate. It has been proposed that herbicide-tolerant GMOs could contribute directly to the rise in herbicide-resistant weeds through cross-pollination with closely related weed species. This explanation is embodied in the oxford dictionary definition of a “superweed”:

A weed which is extremely resistant to herbicides, especially one created by the transfer of genes from genetically modified crops into wild plants

However, According to the WSAA, “The transfer of resistance traits from genetically modified crops to weeds growing in the field is rare.” And according to Dr. Brad Hanson, Cooperative extension specialist at UC Davis, “to date no herbicide-resistant weeds in corn, cotton, or soybean production regions appear to have become resistant due to traits moving from the crop.”

If GMOs did cross with weeds and pass on herbicide-tolerant traits, this problem would not be unique to GMOs, but could also result from crops that have been conventionally bred for herbicide resistance. For example, it is documented that imidazolinone-resistant jointed goat-grass arose from a cross-pollination event with wheat bred to tolerate imidazolinone.

Herbicide-tolerant GMOs could also contribute to the rise in herbicide-tolerant weeds indirectly by encouraging an increase in the use of glyphosate. Glyphosate use has increased with the planting of GE crops, and numbers of glyphosate resistant species are highest for crops for which an herbicide-tolerant GE variety exists.

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Source: Part of the International Survey of Herbicide Resistant Weeds at


However, not all cases of glyphosate resistance have been identified in fields where herbicide tolerant GMOs are grown. To determine if glyphosate-resistant weed species identified for crops that are not genetically engineered for herbicide tolerance arose first in fields where herbicide resistant GE crops were planted, Dr. Andrew Kniss compiled data from and plotted new cases of glyphosate-resistant weeds that initiated in GM-crop sites versus those that originated in non-GM crop sites.

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Source: Data from compiled by Dr. AndrewKniss

Remarkably, cases of glyphosate resistant weeds are no more likely to be documented in association with GM fields than non-GM fields. This is likely because glyphosate is also used in conjunction with crops that are not genetically modified for herbicide tolerance. For example, glyphosate is used to control weeds between rows in orchards and to encourage mature wheat to dessicate so it is ready to be harvested more quickly. If GMOs drastically contribute to the rise of herbicide tolerant weeds, we would expect to see a spike in herbicide tolerance corresponding with the introduction of GMOs; however, this is not the case.

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Source: Data from compiled by Dr. Andrew Kniss



In conclusion, herbicide-tolerance can arise from many sources. Current data do not seem to definitively point to GMOs as a significant cause for the rise in herbicide-tolerance. As Dr. Andrew Kniss puts it:

GM crops don’t select for herbicide resistant weeds; herbicides do. Herbicide resistant weed development is not a GMO problem, it is a herbicide problem.

The European Academies Science Advisory Council agrees:

Cultivating a GM crop variety with increased herbicide resistance, for example, may prove detrimental to the environment if the farmer over-uses that herbicide. But the same would be true of herbicide resistance introduced by conventional breeding.

Despite a lack of clear evidence that GMOs contribute to the rise in herbicide-resistance, many critics cite the development of “superweeds” as a reason for advocating a moratorium on GMOs. Chipotle cites as one of their reasons for removing GMOs from their menu that “GMOs engineered to…withstand powerful chemical herbicides…create herbicide resistant super-weeds.”  Chipotle’s solution to the “super-weed” problem is to switch from using oil from soybeans genetically modified for herbicide resistance, to  oil from sunflowers that are “naturally” resistant to the herbicide atrazine.  As Dan Charles of NPR points out, use of herbicides in this system has led to far more resistance problems. This graph compares numbers of species resistant to the herbicide glyphosate (ESPS Synthase Inhibitors shown in light blue) with species resistant to herbicides used on sunflowers (ALS inhibitors shown in red).

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Source: Graph from, comments added by Dr. Andrew Kniss

Thus, prohibiting the use of herbicide-tolerant GMOs does not eliminate problems of herbicide resistance. Furthermore, according to the USDA, planting herbicide-tolerant crops “makes it easier to manage weeds using less tillage, which can help reduce soil erosion as well as improve soil quality and water conservation”

So if banning GMOs will not prevent the development of more herbicide-resistant weeds, what will? According to the USDA:

Mitigating the evolution of herbicide resistance depends on reducing selection through diversification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank.

The list of best management practices for managing herbicide-resistance includes “cultural practices that suppress weeds by using crop competitiveness,” following herbicide label instructions, and stacking herbicides with multiple mechanisms of action (MOA).  Dr. Stephen Weller, professor of horticulture at Purdue, compares multiple modes of action for weed control with putting more than one lock on the same door: “The thief, in this case the weed, might manage to get by one of the locks, but if you have several, as in several modes of action, it is much harder. If you can control a weed with two or three mechanisms of action, the likelihood of resistance occurring to all the mechanisms used is greatly reduced.”

The USDA has also noted that “Economic Incentives May Encourage Grower Cooperation in Managing Resistance”.

Here are a few other helpful resources on GMOs and superweeds:

Where the Superpowers of Superweeds Comes From. James Schnable, May 14, 2010

WSSA FACT SHEET: Dispelling Common Misconceptions about Superweeds

USDA APHIS Recommendations for Best Management Practices for Authorized Field Trials of Regulated Herbicide-Resistant Crops

USDA: Managing Glyphosate Resistance May Sustain Its Efficacy and Increase Long-Term Returns to Corn and Soybean Production. Jorge Fernandez-Cornejo and Craig Osteen, May 4, 2015

What does Chipotle’s switch to non-GMO ingredients mean for pesticide use? Andrew Kniss, May 18, 2015

Where are the super weeds? Andrew Kniss, May 1, 2013

What are superweeds? & Do GMOs cause superweeds? Genetic Literacy Project, Accessed April 27, 2016


If we’re going to label GMOs, let’s do it sensibly

In my last “Let’s talk biotechpost, I discussed how challenging it is to define whether a genetically improved plant is technically a “GMO”. Determining if a given food item contains genetically modified ingredients is even more difficult.

There has been a lot of recent discussion about GMO labeling. On one side, you’ll hear that consumers have the right to know whether or not food has been genetically modified. On the other hand, many argue that labeling GMOs is unnecessary and would stigmatize a perfectly safe crop improvement technology. Missing from much of this dialogue is an explanation of what would actually be labeled.

There are only a few GMO crops currently on the market in the United States: alfalfa, canola, corn, cotton, papayas, soybeans, squash, and sugarbeets. The majority of GMO crops grown do not show up in the produce aisle directly, but are used to feed animals (alfalfa, corn, soybeans), or for oils (cotton, canola, corn, soybeans) and sugars (sugarbeets, corn) in processed foods.

So where exactly might you find a GMO label if it existed?

1.GMOs or foods containing GMOS

This is obvious. Actual whole GMO produce such as pest-resistant sweet corn, or disease-resistant squash would be labeled. Processed foods obviously containing these ingredients such as salsa with GM corn or trail mix with dried GM papayas would also be labeled.

2.Meat/Dairy from animals fed GMOs

This is a bit trickier, and still up in the air. As Ben and Jerry’s points out on their website, eating a GMO does not make YOU a GMO. For this reason, they have advertised that their ice-cream is “GMO free” for years, even though it is made from the milk of cows fed genetically modified feed. This logic seems fair enough. After all, the gene that makes alfalfa a GMO cannot be found in a pint of Cherry Garcia.

3.Processed foods made with oil/sugar extracted from GMOs

As with meat/dairy, this is a toughy. Just as the genes unique to GMOs don’t make it through a cow’s gut, they also don’t show up in high-fructose corn syrup or soybean oil. These processed ingredients are 100% identical to organic alternatives.

4.Foods produced by (or with ingredients produced by) GM microorganisms

The production pipeline of some foods and food additives relies on genetically modified fungi or bacteria. Cheese is pretty much universally made using enzymes produced by genetically modified microorganisms. Genetically modified microorganisms can also produce vitamins, which can then be used to fortify cereals. This might explain why several vitamins went missing when Grape Nuts and Cheerios went GMO-free. The GM microorganisms themselves are not present in the final product, so the only difference is a decrease in vitamin A, B12, D and Riboflavin in the GMO-free version.

So which of these foods SHOULD sport the GMO label? It’s only physically possible to differentiate those in the first category, raw GMOs or foods containing whole GMOs, from their non-GMO counterparts. Those foods in categories 2-4 are completely indistinguishable from alternatives, so it doesn’t make a whole lot of sense to label them. Nonetheless, you could argue that if you wish to avoid GMOs for religious, economic, social, or environmental reasons, you might want to know if GMOs were used in any step of the production pipeline. In that case, all foods dependent on GM technology should be labeled as such, with no exceptions. Anything in between does not make any logical sense. Unless, of course, you’re Vermont and exempting milk and cheese happens to support your own economic interests…

All of the state-specific labeling initiatives thus far (failed in California, Colorado, and Washington, passed in Vermont) have proposed a patchwork mess with illogical exceptions. Any GMO labeling law upheld in the United States should be national and consistent with no exceptions. That’s my opinion. I’d be happy to hear yours in the comments section.


What is a GMO? This seemingly simple question is difficult to answer, and it’s about to get a whole lot tougher.

It’s no mystery that GMO stands for genetically modified organism, but what exactly does that mean? You might have heard claims like: “we’ve been genetically modifying organisms for centuries”

That’s arguably true. Modern corn is about as similar to its ancestor “teosinte” as corgis are to wolves. Breeding has allowed us to select for useful traits such as large golden grains or small docile canines.  Modern techniques help to speed up the slow, laborious breeding process. “Marker-assisted breeding” involves taking a tiny chip out of a seed coat, checking to see whether a target gene is present, and growing up only the winners. “Mutagenesis” involves using chemicals or radiation to randomly introduce mutations into a population of seeds, and selecting plants with improved traits. Surprisingly, crops produced this way are not regulated as “GMOs” and can even be certified organic.

So what crops are regulated as GMOs? All of the “GMO” crops currently on the market are “transgenic”. As the name implies, this means that a new/foreign gene has been inserted into these plants. This gene can come from bacteria as in herbicide-tolerant or pest-resistant corn, soybeans, cotton, alfalfa, canola, and sugarbeets. It can also come from a virus as in disease-resistant papayas and squash. Transgenic plants can even contain a gene from another plant of the same species. This is the case for the non-browning potatoes and apples coming to market soon.

Seems simple enough right? GMO’s have been directly engineered to contain novel genes. That definition has worked for a while, but now there’s a new trick in a breeder’s box of tools called CRISPR-CAS9. CRISPR-CAS9 is a bacterial defense system that  has all the features of Microsoft Word’s find/replace, cut, copy, and paste tools. It allows scientists to target extremely precise regions of the genome and make very specific changes. For example, if a single mutation is known to cause resistance to disease, scientists can now directly introduce that mutation into an existing gene. This change would be completely impossible to differentiate from a naturally occurring mutation. Nonetheless, many are calling to have plants altered in this way regulated as “GMO,” as they are technically genetically engineered.

So what should really qualify as “genetic modification”? Conventional or marker-assisted breeding, which involves shuffling and scrambling whole genomes? Mutagenesis, which causes unkown mutations at random sites throughout the genome?  Trans-genic technology, which involves adding a single gene that, depending on the gene, might have been possible to introduce by breeding on a much longer timescale?  Gene editing by CRISPR-CAS9 which causes one or a few precise changes to genes?

And these are only a handful of the many techniques used to improve crops. I haven’t even touched on grafting, protoplast fusion, polyploidy, or conventional breeding of non-compatible species with chemical assistance! You can see the issue is pretty complicated. Perhaps the real questions should revolve around risks not processes. Why continue to heavily regulate any crop produced by transgenic technology when every major scientific organization in the world has agreed the technique is no more inherently risky than conventional breeding? And why regulate crops produced by gene editing which causes one or a few precise changes, but not those produced by mutagenesis which introduces many unknown mutations?

I’m happy to hear your civil and respectful thoughts on which crop improvement technologies should fall under the GMO umbrella in the comments section.

For more resources, there is a great infographic by Dr. Layla Katiraee of Integrated DNA Technologies comparing different crop improvement techniques, and a very thorough analysis of the GMO definition problem by Grist science journalist Nate Johnson titled “It’s practically impossible to define ‘GMOs’