Genetically modified crops are a topic of intense debate that have sparked a lot of controversy over the years, fuelled largely through a lack of understanding and vast amounts of misinformation. Do we need GM crops? Are they dangerous? This article is going to give a brief overview of this huge topic and also discuss some of the myths and facts of GMOs.

What Are GMOs?

Humans have been modifying the genomes of plants and animals for our benefit for thousands of years using a process known as artificial selection, or selective breeding. This involves selecting organisms with desirable traits and breeding them so that certain characteristics are perpetuated. This could be a teacup dog, a cow with improved milk production or a fruit without seeds. However, this is limited to naturally occurring variations, which is where genetic engineering has found a place.

Selective breeding over time has dramatically changed corn. Image credit: John Doebly, via Wikimedia Commons.

Genetic engineering allows us to introduce genes into an organism from a totally unrelated species which is commonly carried out on crops, agricultural animals and bacteria. These genetically modified organisms (GMOs) are designed for many reasons, including: pesticide and disease resistance, drought/frost resistance, increased yields, enhanced nutritional content and as a way to produce drugs or vaccines at low cost on a large scale. When most people consider GMOs they think of agriculture, but the medical implications are wide ranging. For example, genetically engineered bacteria now produce insulin, saving the lives of millions of type 1 diabetics.

Why Do We Need GMOs?

While it is true that a major problem with feeding an over burgeoning global population relates to the distribution of the food that we do produce, if population growth does not slow down then we are going to need to find new ways to meet food demands. The Food and Agriculture Organization of the UN has estimated that we will need to grow 70% more food by 2050.

There are several ways that this could be achieved. We could destroy valuable rainforests to make way for agricultural land, but I don’t need to go into the reasons why we should not do this. We could stop eating as much meat, given that the crop calories we feed to animals could meet the calorie needs of 4 billion people, but few are willing to do this and meat consumption has quadrupled in the last 50 years. We could invest more in hydroponics (growing crops efficiently indoors, without soil), which is what many countries are looking into. Or we could create GM crops.

Hydroponics. Image credit: Remi Jouan, via Wikimedia Commons.

Many things threaten food security, such as crop or animal diseases, pests and climate change. Weather is becoming more unpredictable and extreme weather is becoming commonplace which is taking its toll on farmers worldwide. The idea behind many GMOs is to address these problems.

Tomato with blight. Image credit: Downtowngal, via Wikimedia Commons.

Examples of GM Crops

An excellent example is golden rice. Around 250 million children are vitamin A-deficient in the world, which kills and blinds millions each year. While supplement distribution programs exist, they’re expensive and difficult to sustain. The solution? Golden rice.

Researchers added two genes to white rice, one from a soil bacterium and another from the daffodil, which synthesize a precursor of vitamin A called beta-carotene. This pigment makes various foods orange and hence makes the rice appear golden. The daffodil gene was later swapped for a corn gene to further increase the amount of beta-carotene produced.

White rice is a staple food in many countries but it’s not usually a source of vitamin A. One bowl of golden rice meets 60% of a child’s daily vitamin A needs. However, this product has been met with significant opposition, especially from Greenpeace, mainly because many people believe it will lead to widespread acceptance of GMOs. The fact remains: it’s a viable solution to a real world problem. It was also developed by foundation-funded academic researchers and a nonprofit organization, not a big private corporation.

Image credit: International Rice Research Institute, via Wikimedia Commons.

You may also be surprised to find out that around 85% of corn grown in the U.S. is genetically modified. Soy is also heavily genetically modified; one particular soybean was engineered to produce high levels of oleic acid because it is thought that this may lower LDL cholesterol, or “bad cholesterol.”

Controversies Surrounding GMOs

There are many controversies surrounding this topic. Some are complete myths, while others raise valid issues.

Labeling

It is estimated that as much as 90% of commodity crops used in the U.S.’s food supply are genetically modified. Few people are aware of the extent of GMOs because the food industry does not label them through fear of sparking safety concerns in customers. Some have suggested that labeling would be like putting a skull and crossbones on packaging; however, people argue that they should be able to know what they are eating so that they can make an informed choice.

Mandatory label laws have come into place in certain countries, but they have not resulted in the anticipated reaction. Instead, they have led to an increased pressure for retailers to stop stocking GM products which has reduced consumer choice and at times raised prices. It should be stressed that despite decades of testing, there is no evidence that genetically modified foods are intrinsically more dangerous or worse for you than unmodified food. This fear-mongering then, can come across as anti-science.

Transparency is a hallmark of good science, but when the public does not fully understand the topic it can fuel fear. Mandatory labeling is therefore a complex issue with valid points from both sides. "GMO" is a fairly meaningless term when applied alone. Genetic modification is just a technique, it is not inherently dangerous. As with all techniques, it's how it's used that matters. Labeling food as "GMO" wouldn't tell you how it was modified, just that it was. A food label with "GMO" written on it really doesn't tell you anything more than "there's science in this food".

Risks To Health

While the genes inserted into organisms occur naturally in other species, there are concerns that altering the natural genome may have unknown consequences. For example, modifications may change the organism’s metabolism or growth rate. There are also concerns that GM foods may expose new allergens to humans or transfer antibiotic-resistant genes to the bacteria naturally found in our gut.

A lot of fear was sparked about the safety of GM foods after a scientist named Gilles-Eric Séralini published a study that found rats fed with Monsanto’s glyphosphate-resistant corn developed more tumors and died earlier than controls. After these results, many demanded tighter regulations whereas others called for an outright ban on the corn. However, numerous problems with the study came to light which led to its retraction from the journal.

First off, Séralini is an outspoken anti-GMO activist. At the time of initial publication he had conflicting interests- he was releasing a book and a documentary on the research. For the experiments, Séralini used Sprague-Dawley rats that are prone to developing spontaneous tumors. He also only used 10 rats for each group, for a period of two years which is almost a rat’s lifespan. The study was described as a "statistical fishing trip" by reviewers - if you test enough variables for long enough, you'll get a result from something. This is not good science. The recommendation for carcinogenicity studies is that 65 or more of each sex should be used. There is a high probability that the results were due to chance.

Furthermore, there have been mounds of better designed studies that have found no health issues, further suggesting that poor study design is the likely reason for the results, not the GM maize.

Terminator Seeds

Research on genetic use restriction techniques (GURT), or more commonly “terminator seeds” or “suicide seeds,” aims to produce sterile seeds/offspring so that if modified plants escape, they cannot propagate in the environment. The idea that companies use these to force farmers into continually buying seeds is a myth .

This technology would be useful in the development of “bioreactor” plants, for example those used in the production of pharmaceutical products such as antibodies or drugs to stop unintended gene release.

People don’t realize that sterile plants are already widely used- take a look at seedless bananas or grapes, but have they enslaved farmers? This technology is necessary and restrictions in the development of GURT harm research into the generation of beneficial crops.

Image credit: Stephen Ausmus, via Wikimedia Commons.

Separating Corporation from Technology

Everyone has heard of Monsanto, and this company is frequently cited as a reason to oppose GMOs. While Monsanto’s business practices may be ethically questionable, Monsanto are not the only company involved in GMO research. Many non-profit organizations and academic institutions are involved in this field. The technology is necessary and disagreeing with Monsanto and having anti-corporation values should not muddy your views on GMOs. If you have a problem with Monsanto, have a problem with Monsanto. Don't extend that to every application of GMOs.

Image credit: Luther Blissett, via Wikimedia Commons.

GM Crops Result In Superweeds

Many farmers use herbicide resistant crop varieties, for example GM cotton that can tolerate Roundup. This was very successful initially until herbicide resistant weeds evolved and rampantly spread in various countries, causing huge crop losses. While it has been argued that these GM crops encourage the evolution of herbicide resistance through liberal use, the fact is: it happens whether we use GM crops or not.

Monsanto argued that farmers did not need to adopt traditional methods used alongside herbicides such as crop rotation or varying the chemicals used, which slow herbicide resistance. The studies they carried out in support of this statement were flawed and criticized, which has now led to Monsanto changing its stance and encouraging plowing and a mix of herbicides.

Herbicide resistant crops do have their merits, though, and have caused a significant reduction in herbicide usage and an improvement on environmental impact.

Image credit: USDA, via Wikimedia Commons.

Unintended Spread Of Genes

There has been concern that genes used in the development of GM crops may unintentionally spread to other organisms through a mechanism called horizontal gene transfer. For example, antibiotic resistance genes are regularly used in the process of genetic modification, and there is concern these genes may spread into bacteria, animals or humans, encouraging the spread of disease. While this is a possibility, studies have found that the risks are negligible and that transfer rates are exceedingly low. However, recommendations have been made to avoid using antibiotic resistance genes in creating GMOs.

Outcrossing

A final concern with GM crops is that genes may spread from these plants into conventional crops or related species found in nearby areas, a process known as outcrossing. This could have ecological consequences, such as an increase in fitness or a decrease in genetic diversity. These risks are recognized and measures have been adopted to minimize them, for example engineering the plants so that transgenes are not incorporated into pollen or separating fields containing GM crops and conventional crops.

Genetic modification is simply a tool. Like all tools, the application is what matters. All new technologies require review and testing, but fears should be based on science and evidence, not a lack of understanding when it comes to new science.