GMOs Pt 4: Is the Apocalypse Nigh?

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Disclaimer: Trading Atoms has no interests, financial or otherwise, in any biotechnology or related company.

Genetically modified (GM) crops are playing an increasingly significant role in global agriculture, and quite literally changing the face of our planet. Unfortunately, science has a rich history of inadvertently messing things up, which raises a question: should we be concerned about GM crops too? There are five major worries that people commonly hold regarding the technology:

  1. GM food is dangerous for human health
  2. GM crops lead to increased pesticide use
  3. Farmers are exploited by biotech companies
  4. Genes from GM plants might spread into the wild
  5. Triffids?!

If you’ve already read up on What Genetic Modification Is and What the Heck is Out There, you have all the background needed for us to turn up our coat collars, dive boldly in and see where the evidence leads on these questions.

 

Chemicals and critters

We’ve mentioned previously that of the millions of hectares of different GM crops out there, just two types of modification account for almost all of them: herbicide tolerance and insect resistance. It’s worth understanding these in a bit more detail before addressing the five major worries.

Herbicide tolerance is a modification that allows plants to survive a synthetic chemical called glyphosateGlyphosate was created by Monsanto in the 1970s and brought to market as “Roundup”. After their patent expired in 2000, glyphosate use expanded greatly, soon becoming the most widely used herbicide in the world. It has been described as a “one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling diseases.” This weighty claim is worth taking seriously.

Glyphosate interferes with a protein called EPSPS which is critical for growth. This protein is only found in plants and bacteria, meaning glyphosate has minimal toxicity toward humans and other animals. It is also cheap, has a relatively short half-life in the environment, and has replaced the use of several more toxic and persistent herbicides.

“Roundup Ready” plants, developed by Monsanto, contain a modified copy of the EPSPS gene which lets them grow even in the presence of glyphosate. This means that farmers can spray glyphosate on their Roundup Ready crop, and only weeds and competing plants will be killed. This represents a vast simplification of pest management strategies.

Fun fact: the modified EPSPS gene was isolated from a bacterium found growing in a glyphosate manufacturing waste stream.

 

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Micrograph of a colony of bacillus thuringiensis

The other major crop modification, insect tolerance, is achieved by giving plants a gene to make “Bt”. Bt is a naturally occurring protein that gets its name from its creator: Bacillus thuringiensis, a common soil bacterium. A simple overview of the Bt system is provided by the European Commission.

When Bt is ingested by an insect, it is activated by the alkaline environment of the insect’s stomach and becomes toxic. It interferes with the insect’s digestive tract, eventually causing the insect to starve to death. Because humans and other vertebrates have acidic stomachs, any Bt ingested remains in its non-active form, and is therefore not toxic. A review from the European Food Safety Authority (see p. 8) reached this same conclusion of Bt non-toxicity in mammals. Furthermore, Bt is only harmful to insects that ingest it, meaning that beneficial insects like honeybees, which don’t eat crop plants, are left unscathed.

Bt has been used as an insecticide since the ’60s, when it was approved in Germany as a spray. Because Bt is a naturally-occurring product, it is also commonly used on organic farms as a spray – there’s a good chance your organic kale was grown with the help of Bt. Genetically modified Bt crops let farmers skip the spraying step, instead making the protein automatically inside their cells, where it will only harm any insects which eat the plant.

Now we’ve covered the two main GM technologies, let’s tackle the five major worries!

 

1. Is GM food dangerous for human health?

It turns out that this question has the clearest answer of all: GM food is in no way dangerous to human health. Follow this link for more information and references about the safety of GM food than you could possibly care to read. In short though:

“There are nearly 2000 peer-reviewed reports in the scientific literature which document the general safety and nutritional wholesomeness of GM foods and feeds.”

 

A selection of the many scientific and medical organisations that have publicly supported this assessment:

14-12-01 The science of genetically modified food

For a GM crop to be certified as safe for human consumption by organisations like the FDA, it must display “nutritional equivalence” to its non-GM counterpart. Remember, the fundamental change in a GM plant is that it has a few extra genes sprinkled amongst tens of thousands of genes, making one extra protein amongst tens of thousands. This means that nutritional equivalence is not surprising.

The main risk of introduced proteins is that they could cause an allergic reaction. Accordingly, allergenicity testing is a strict requirement for any proposed GM crop. This testing is effective, and to date, “no biotech proteins in foods have been documented to cause allergic reactions.” Interestingly, GM technology can actually be used to go the other way, remove existing allergens from food.

If you have any lingering doubts about the health safety of GM food, hopefully this 29-year study of over 100 billion GM-fed animals will satisfy them.

 

2 & 3. Do GM crops lead to increased pesticide use, and are farmers exploited by biotech companies?

We’ve seen that Roundup Ready crops can survive copious spraying of glyphosate. Could this encourage farmers to apply the chemical recklessly? If so this is a worry, as the more glyphosate that is used, the more pressure there is on weeds to develop resistance, necessitating the use of ever greater quantities of glyphosate. As for exploitation of farmers, claims along the following lines are well-known: “Roundup Ready crops do not increase the yield or profits of farmers, [and so] only serve to benefit Monsanto.”

To address these two issues, we turn to the latest and most comprehensive peer-reviewed meta-analysis of the economic impacts of GM crops, published in 2014 in the journal PLOS ONE.

The authors screened over 20,000 agronomic studies, narrowing down to a set of 147 which met stringent criteria for inclusion. They analysed a range of factors, including yield, pesticide use and farmer profits. Here are their results when comparing GM crops to conventional ones. *** indicates high statistical significance (at the 0.01 level):

journal.pone.0111629.g002

So they found that, on average, GM crops increase yield by 21.6%, decrease pesticide used by 36.9%, and increase farmer profits by a whopping 68.2%. There is no significant effect on total production cost. As the authors explain, although GM seeds are more expensive than conventional ones, this cost is offset by savings in pesticide use and manual pest control.

These results may come as a surprise; however, the story changes when we separate out herbicide tolerant (Roundup Ready) and insect resistant (Bt) crops. Analysed on their own, Roundup Ready crops only increase yield by about 9% (compared to 25% for Bt crops), and while both types of modification increase farmer profit by around 68% on average, this figure is extremely variable for Roundup Ready crops. It seems that they are sometimes great for profits (150% increases or more), but other times they actually hurt profits badly (-24% or worse). Also notably, the decrease seen on the graph in pesticide use is due entirely to Bt crops (which use 42% less than conventional crops). Roundup Ready crops seem to need just as much pesticide as conventional crops.

The take-home message is that not all GMOs are created equally. Overall, genetic modification has been a great boon to farmer profits and played a role in decreasing pesticide use, but it will be necessary to evaluate each new modification on its own merits.

 

4. Can genes from GM plants spread into the wild?

Is it possible that GM crops could escape into the environment and run rampant much like an introduced species, or perhaps breed with weeds/wild relatives to create a so-called “superweed“?

First, the scary news: breeding of crop plants with wild ones occurs constantly. Rapeseed can mate with turnip rape, genes from cultivated maize can cross to wild maize, and sugar beet can form hybrids with garden beet. This process happens for both GM crops and crops bred over time for selected traits.

Furthermore, it turns out that glyphosate-resistant weeds have already emerged, with half of all U.S. farms now struggling to control these pests. While this is a serious issue for food security and highlights the danger of relying on a single pest-control mechanism, the resistance is not due to GM genes escaping. Rather, it has evolved independently in the weeds. Such evolution is ubiquitous and inevitable, and the same process underlies multidrug-resistant bacteria, insects overcoming every insecticide ever made (including Bt), and why effective cancer drugs are extremely difficult to develop.

Short of some game-changing technological breakthrough, humans will always be locked into these evolutionary battles against pests and diseases.

Regardless, do we need to be concerned about the spread of GM genes? It depends on the modification, but the answer will often be “not really.” To understand why, let’s consider a critical Darwinian question:

“Will the extra protein(s) give the GM plant an advantage over wild ones?”

It costs a plant resources to make proteins, so if those proteins don’t do something to give the plant a leg up over its competitors, the plant won’t spread. Glyphosate doesn’t exist in nature, so building glyphosate-resistance proteins is just dead weight.

On the other hand, there are modifications, such as faster growth or insect resistance, that could conceivably give a GM plant an advantage over competitors – Bt is a good candidate. In these cases, management strategies such as seed sterility, buffer zones, and altered flowering timing are critical for ecological safety.

There are no known instances of GM plants spreading genes into the environment – although interbreeding with non-GM crops is another issue (maybe for a future article) maybe for a future article. At this point the risk seems manageable Once again though, genetic modifications will have to be scrutinised on a case-by-case basis.

 

5. Triffids?!

 

Biological traits like mobility and intelligence are super complicated to even understand, let alone engineer. We’re probably safe on this front for a long while yet.

 

Do we actually need GM crops?

We’ve seen that, thankfully, a lot of the criticisms and worries around GM crops don’t stand up to scrutiny. It’s clear that, overall, GM crops have increased yield and farmer profits, decreased pesticide use, and are safe for human consumption. Nonetheless, it may be worth considering whether we really need GM crops. There will always be unknown risks involved in tampering with complex systems such as global agriculture, and these unknowns may exceed the known benefits.

One of the strongest arguments in favour of GM food rests on the projected global population for the coming century, which is set to increase significantly. Agriculture already covers about a third of the world’s landmass, and short of further deforestation, there simply isn’t more space to devote to it. This means that if we are to feed a growing population, yield per hectare will have to increase. It will be difficult to achieve these increases without (and possibly even with) turning to GM technology – especially in the face of climate change.

Another argument is one of humanitarianism and international development. Contrary to common perception, 90% of GM crop farmers live in developing countries, largely China and India, and till small resource-poor farms. We have seen that GM crops typically lead to increased yields and profits for farmers. Anecdotally (see link above), this extra income often goes to financing things like improved access to health care and education.

Maybe the apocalypse isn’t quite so nigh as we may have feared.

Want to learn more? Two reputable and well-researched websites are the Genetic Literacy Project, and the European Union’s GMOcompass.

GMOs Pt 3: What the Heck is Out There?

Disclaimer: Trading Atoms has no interests, financial or otherwise, in any biotechnology or related company.

Welcome to the third part of this mini-series on Genetically Modified Organisms (GMOs), where we’ll take a more detailed look at what the heck is out there in the environment. If you’ve just tuned in, you might like to first read up on what exactly genetic modification is, and maybe how to make your very own GMO.

Let’s start with some context by taking a starry-eyed look back over 10 of the most significant developments in GMO technology that have led up to today.

A Montage of Genetic Modification

1953: Watson, Crick and Franklin discover the structure of DNA.

1973: Boyer and Cohen create the world’s first ever GMO when they modify the bacteria E. coli to express an antibiotic-resistance gene. In the process they unintentionally foreshadow a serious problem soon to hit the world: the evolution of antibiotic-resistant bacteria in hospitals.

1974: Jaenisch and Mintz create the first GM animal. They injected a primate virus into mouse embryos, then transplanted the embryos into surrogate mothers. The mice grew up normally except that they contained the viral DNA.

1978: Genentech, the world’s first genetic engineering company is founded, and engineers E. coli that can produce human insulin. Diabetics and livestock everywhere rejoice.

1980: The U.S. Supreme Court rules 5 to 4 in General Electric’s favour that “A live, human-made micro-organism is patentable subject matter”. In so doing, it sets the entire course of GMO history to come. GE immediately patents a bacteria engineered to eat crude oil.

1983: The first modified plant is created, again by adding an antibiotic resistance gene. Can you guess the species? (Hint: it was the ’80s). Yep, of course it was tobacco.

1987: The first field release of a GMO takes place – a “Frostban” bacteria designed to protect crops from frost. Activists attack and attempt to sabotage the trial site the night before. It’s said that history repeats.

1994: Calgene produces the first commercial genetically modified (GM) crop plant, the Flavr Savr tomato. This tomato doesn’t produce a natural protein that degrades cell walls, meaning it stays ripe for longer. The Flavr Savr experiences a tumultuous commercial life of initial success, then by a decline at the hands of consumer distrust, and finally discontinuation by 1997.

1995: The commercial GMO market explodes, with the development of potato, cotton and maize strains that can resist insects.

In the ensuing two decades, two particular classes of modification have come to dominate the GM plant market: insect resistance (via insertion of the “Bt” toxin gene), and resistance to the herbicide “glyphosate” (marketed as Roundup). Glyphosate resistance now dominates the GM market to such a degree that it is present in a whopping ~90% of all transgenic crops, making it the Big Cheese of commercial GMOs. We’ll talk about this as well as Bt in the next instalment.

How many GMOs are out there?

To date, all GMOs approved for human consumption have been plants. A common source of confusion regarding this claim is recombinant bovine growth hormone (rBGH), which is injected into dairy cattle to increase milk production. rBGH is produced by genetically modified bacteria, in much the same way as human insulin. Injecting rBGH into cattle doesn’t cause them to become genetically modified. It is however a form of doping, one which is demonstrably harmful for their health and wellbeing. Human growth hormone has been abused by athletes since the ’80s.

So, why haven’t GM animals been commercialised (except for certain novelty uses)? There are a few possible reasons. Plant products make up the bulk of the average person’s diet, and consequently plants account for the majority of the value of the agricultural sector. Aside from this economic incentive, plants are arguably easier to modify and cultivate than animals.

Nonetheless, there’s also a clear legislative bias at play against commercialising GM animals. This may reflect an unproven notion that there’s less risk of GM plants escaping and spreading. A more reasonable argument might be that because plants lack sentience, there’s no risk of them suffering because of a modification. The main reason for the bias may not be so rational though.

Since animals are our closest evolutionary ancestors, we typically hold them in a more reverential and even “sacred” light than plants. You can probably imagine a mutant two-trunked pine tree without being too bothered, but a two-headed rat feels a lot more uncanny valley.

Whatever the reason, at this point in history, crop plants are the undisputed stars of GM technology, so we’ll refocus our radar in the direction of agriculture.

 Delicious Data About Agriculture

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Agriculture covers a full third of the Earth’s land area, and as of 2013, GM crops made up about 3.5% of the total. That corresponds to more than 1.7 million square kilometers, or an area greater than the entire landmass of Iran. Given this, it’s probably fair to say the prevalence of GMOs is not insignificant.

Legal regulations and social attitudes towards GMOs vary widely between countries, which means that these crops aren’t just scattered around the globe randomly. A particularly rich source of information on GM crops is the report Global Status of Commercialized Biotech/GM Crops: 2012, commissioned by the pro-GM group ISAAA (The International Service for the Acquisition of Agri-biotech Applications). Despite their partisanship on the issue the data seem solid, and the report is worth a read if you’re interested in details about a particular country’s GMO activities.

Which nations are the biggest adopters of GMOs? There were only 28 countries growing GM crops as of 2012, though these countries are home to 60% of the world’s population. Uptake is overwhelmingly focused in North and South America. Interestingly, and largely owing to Europe having the strictest GMO regulations in the world, there are only eight industrialised countries growing GM crops, meaning the rest are developing nations.

Most GM-growing nations are currently focusing on cotton, maize and soybean. GM food crops are predominately used as livestock feed rather than for human consumption, and as mentioned earlier, most GM crops are herbicide resistant and/or insect resistant. This is changing though, with an increasing proportion of “second generation” strains entering the market, which have these traits stacked with others, such as enhanced nutrition or drought tolerance. The USA and China are cultivating GM versions of several other food crops, including things like papaya, sugarbeet and sweet pepper.

While the USA has the greatest land area devoted to GM crops of any nation, as well as the highest number of GM species, GM land is mostly devoted to just a few staple crops, for which an extremely high proportion grown are GM varieties. For the “big three” of cotton, maize and soybean, over 90% of farms are now growing GM varieties. In Canada, a record high of 97.5% of canola crops are GM.

The increasing uptake of GM crops is an interesting story. Despite the USA easily dominating the pack in this modern day space race, the vast majority of remaining GM crops – and 90% of GM farmers – are located in the developing world. Developing nations are also taking up GM technology at a greater rate. As you can see in the chart below, industrialised nations have already lost the majority share of the market.

How do we explain the huge differences in GMO legislation and uptake rates between countries, particularly Europe and the USA? It’s worth first reminding ourselves that, by many metrics, the USA is just a weird outlier, so this may be a very difficult question to answer.

Nonetheless, one possible explanation is labelling requirements (though the causality is hard to tease apart). In the late ’90s, a strong opposition movement to GMOs grew in Europe, and it succeeded in mandating strict labelling of any GM products. Supermarkets responded with a wave of panic, banning products containing any GM ingredients out of fear of losing customers. In a very short time, the entire European GM industry was dead. Conversely, see North America on the graph below (click for larger version). It has no labelling requirements.

Without labelling of GM products, there is less consumer concern and less avoidance of them, meaning the economic incentive for farmers is to grow GM crops rather than less efficient conventional ones. Is this a bad situation for the USA? This debate is currently raging in several US states, with recent or upcoming votes on GMO labelling. All we will say here is that when public concern is coupled with scientific misunderstanding, the outcome can be quite harmful.

Unravelling Some Sticky Side-Issues

Neil deGrasse Tyson was recently lambasted for defending GM technology by claiming it is not all that different from the domestic selection that humans have been exerting on plants and animals for thousands of years. As he pointed out when he later clarified his statement, there is a big sticky mess of related issues tangled up with GMOs, and it was these that his attackers mostly took issue, not the science itself. It’s worth dissecting out a couple of these confounding topics before closing the book on current GMO status.

The sticky mess includes things like: corporate exploitation of small farmers, monocultures, and the merits of “organic” farming (a term that every organic chemist will tell you is meaningless as they sigh into their erlenmeyer flask).

1. Corporate exploitation and patenting. Tales are rampant of farmers in developing countries being forced into unfair annual contracts for GM seeds, or of organic farmers losing their organic licence then being sued because their crops have been contaminated by a GM strain. Such situations rightly invoke our moral outrage. However, according to the excellently researched and independent Genetic Literacy Project, these stories simply aren’t true. Some are myths while others have the facts twisted. Even if these tales were true though, lawsuits and rigid contracts are issues of equitable IP legislation, not of science. The same problem applies to the pharmaceutical industry, with potentially life-saving medications being fiercely protected by patents and kept artificially expensive.

2. Monocultures. A common claim is that GM crops are always “monocultures”, meaning genetically identical plants are grown en masse. The risk here is that if a virus or pest evolves which one plant is susceptible to, all would be susceptible, leading to rapid losses of huge numbers of plants. As it turns out though, when a GM plant is developed, the trait is typically bred across into many cultivars in order to increase the genetic diversity and minimise this risk. That said, growing only one type of crop in an area does harm soil quality and biodiversity and so should be avoided where possible. Most GM crops, excepting pesticide resistant ones, can be grown in mixed plots with no barriers.

3. Organic food. The main point to stress here is that GM crops are not the opposite of “organic” crops. While organic farming excludes the use of GMOs on ideological grounds, it is primarily an alternative to conventional large-scale agriculture. You could grow a patch of GM alfalfa using entirely organic farming practices if you wanted to. Despite this, GMOs and organics are often pitted against each other in the context of food production and security.

Whatever merits organic farming may have, superior food production is sadly not one of them. A 2012 meta-analysis published in that most weighty of scientific journals, Nature, found that organic farming typically produces 34% lower yields when compared to conventionally farmed crops in comparable conditions. This entertaining and well-researched video explores the pros and cons around organic food and dispels some common myths.

If you’ve made it this far, congratulations! You should now be clued up on exactly what genetic modification means, where GMOs come from, their history, and what the heck is out there at the moment. This means it’s time to face the upcoming last part in the series: GMOs Pt 4: Is the Apocalypse Nigh?

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