GMOs: next revolution or hazard to avoid?

GMOs are one of the most controversial subjects of recent years. So much, that not a month goes by without some kind of a scandal appearing in your local newspaper. For example, a moratorium on the use of GMOs has been in force since 2005 in Switzerland and continues to be extended by the government [1]. Yet one might imagine, that with so much discussion about it the general public will be well informed, and aware of its possibilities and its risks. However, it would appear that the population remains very concerned about the possible negative effects of GMOs: only 3 out of 10 Europeans consider that an apple that has integrated a  gene from another species does not present a risk [2].

GMOs – what is it?

When talking about GMOs, some people can get confused about how they are produced, or what’s the purpose of their use. And usually, when people do not understand something, they can easily get afraid of it or misinterpret more subtle details about that subject. GMOs are no exception to this rule. 

As the acronym indicates, GMOs are “organisms” that are “genetically modified” [3]. The definition is sometimes considered controversial, because selective breeding [4] is a kind of indirect genetic manipulation, as we will see just below. Generally speaking, GMOs describe only the organisms that have been modified with genetic engineering techniques, which don’t include “natural modifications”. In other words, GMOs don’t concern the modification that can occur spontaneously in nature (such as spontaneous mutation [5], selective breeding [4] or recombination [6]), without human interference. 

Genetic manipulation can be useful, and we, as a society, actually profit from it on a daily basis. The selective breeding of plants is one of many examples where genetic engineering is involved. Indeed, the fruits and vegetables that we are eating are the product of years of selection of genes and traits, that they determine beneficial to human consumption. This is why most of the commercial plants found on the market are bigger and more attractive than the one found in nature (see picture). We also have already “created” some new species, for example by breeding two fruits to obtain a new plant, with a mix of two characteristics. This was the case of the clementine, a product of breeding between a mandarin and an orange [7]. These breeding events can actually happen without our intervention, we just simply forced a rare event to happen, to use it to our advantage.

As many biological technologies, the production of GMOs are based on phenomenons and reactions that already exist in nature but are just manipulated by humankind. The idea is to modify the genome of an organism to express a beneficial gene, remove some disadvantageous ones or introduce some new genetic material from another species. The action can actually be very variable, depending on the goal of the modification. However, the man-made manipulations are usually minor, to minimize the impact on the rest of the genome and the organism. In fact, the DNA and its expression is a very complex process that involves a lot of interactions. It is then difficult to induce a lot of changes while also knowing the exact impact that it will have on the organism. This is why the introduced modifications are generally small and carefully considered.

GMOs and their stereotype 

While talking or searching about GMOs, it is possible to hear a lot of different facts that can be accurate or completely wrong. Let’s first review some stereotypes that were not scientifically confirmed.

• Consumption of GMOs will lead to DNA modification, cancer or other diseases

Technically speaking, a GMO is only an organism whose DNA has been manipulated. Every day, we eat proteins, genes and entire genomes without any problems. As every aliment that contains DNA, GMOs´genetic material will be digested in our stomach and reduced into small pieces, called nucleotides [9]. The modifications will then technically have no impact on the consumer’s DNA [10].

Of course, it is not possible to guarantee a 100% safety with the actual knowledge and the research allowed. Let’s take a simple example to illustrate the problem. One of the goals of GMOs can be, for example, to increase the concentration of a molecule in a fruit to make it tastier [11]. This could be done by over-generations selective breeding, but modifying the DNA directly is faster and cheaper. It is then totally possible that this protein, in high concentration, gives a better taste to the fruit but also gives an allergic reaction to people, because the body is not used to receiving such high concentrations of this molecule. To really be aware of the possible impact that the GMOs could have, it is then really important to be allowed to test them and design a security test protocol, as it’s the case for every product put on the market.  

• GMOs are “unnatural”

This is more of a philosophical question, and everyone can have their own opinion on it. It is just important to remember that some of the manipulations made in GMOs give the same results as “natural” manipulation, but faster. As said before, the breeding and plant selection is just a longer and more expensive way to manipulate the genome of plants. Moreover, depending on the organism used in the genetic manipulation, it is possible to only use its preexisting natural capacities to modify it. This process is called horizontal genetic transfer [12]. This is the case for bacteria for example, who can naturally intake DNA or exchange it, to acquire new characteristics (for example new resistance to antibiotics) [13].

• GMOs are the best solution to every problem

Of course, GMOs are not the perfect solution to all of the problems in the world and will not solve everything in the blink of an eye. But it can surely be a useful technology and could be part of/one of the solutions to some of the current problems we are facing. Among others we can mention, saving local production from pathogens such as Hawaiian papaya [14], reducing the nutrition deficiencies of whole populations with “golden rice” [15] or proposing innovative solutions to combat serious diseases such as GMO mosquitoes [16]

Negative side of GMOs

Even if GMOs have a bright side, a lot of concerns are still present, and it should  be kept in mind. Here are a few examples of the current struggles linked to the production and use of GMOs.

• Super resistant pathogens

One of the uses of GMOs is to produce plants that are resistant to pesticides that are used to kill parasites and pathogens. The negative aspect of this procedure is that pathogens and parasites slowly gain resistance, because of the selective pressure that the strong treatments are imposing. Indeed, a stronger treatment can lead to the disappearance of some parasites, but also to the emergence of new, stronger ones that have adapted [17]. The resistance gene could also be transferred in pathogenic bacteria that could acquire new resistances [18]. We can then face, as with every treatment, a resistance that could be harder to get rid of.

• Uncontrolled spread

The main problem with the GMOs is the risk of not controlling their spread. Depending on the modification made, it can bring a lot of advantages to some other organisms (pathogenic bacteria acquiring new resistances) or invading some natural spaces (uncontrolled spread of seeds). This is one of the main current concerns with the GMOs and explains why research and usage of GMOs is tightly controlled in some regions [1].

• Allergies 

Even if GMOs have not been related to diseases, it can happen that some people will react badly to some of them and develop an allergic reaction. This is however not really surprising or especially linked to the GMOs. Indeed, food in general can cause various reactions in different people. When a new product is used, some people will develop an allergic reaction. This is not because the product is toxic, but because the body overreacts when facing the new product. Allergic reactions when eating GMOs are then not linked to the genetic modification, but to a reaction that is happening with food in general [19, 20].

• Safety and risk

For the moment, the scientific community has not agreed on the safety of GMOs uses. Even if no studies have proven that GMOs don’t affect the health in general (except for some allergic reactions), too few tests have been done and authorized to reach a consensus [21]. This situation is on one side blocking the possibility to test more, and maybe give access to a new powerful tool, but is more cautious in terms of safety. 

• Monopoly of agricultural companies

Another one of the biggest problems with GMOs today is not a scientific, but economic problem. The introduction of GMOs into agriculture raises a number of concerns, including the potential monopoly that could be imposed by large companies and the increase of seed prices [22]. In the United States, for example, where the use of GMOs in agriculture is allowed, the monopoly that Monsanto Company, DuPont Pioneer, Dow AgroSciences and Syngenta are imposing is causing great controversy  [23]. According to AgWeb, these four companies alone have held 80% of the US corn seed market and 70% of the soybean seed market in recent years [24].

Positive side of GMOs

• Reduce use of chemicals

GMOs could have many applications. Concerning the plants, one of the common arguments is the reduction of the chemicals used against pathogens or to increase growth.  As a matter of fact, it’s possible to integrate increased immunity or growth factor directly in the genome of the plant, which would allow the plant to get rid of many  pathogens without having to use dangerous chemicals [25]. This could then also have a great impact on the environment and pollution. 

• Better yield and better growth

As mentioned before, one of the other applications that could be made with GMOs (mostly for plants) is the improvement of growth (to increase the yield) or to boost the production of various vitamins and proteins. It could be notably used in regions where the plants have fewer resources to grow or where the population suffers from malnutrition, as it was already done with the “golden rice” project for example [15].

• Medical purpose 

We usually think about plants and food when we are talking about GMOs, but there are actually many applications, in all kinds of fields. The second main application of GMOs would be in medicine [26]. It is actually already used in some cases. One of the most famous examples is the production of insulin. The current one is produced by genetically modified bacteria containing human genes. It allowed a cheaper production and an easier purification of the product. Obviously, given the fact that it is produced based on the human gene, it reduced the risk of rejection from the patient [27]. This simple example illustrates the possible benefits of GMOs. 

• Environmental purpose 

The GMOs could be used as well for environmental purposes. As said before, it could impact the agriculture field and how we are growing our food. It is also possible to develop bacteria to digest plastic, which is a rapidly raising problem at the moment, [28] or to decontaminate water [29].

In summary, both the scientific community and the public haven’t arrived yet at a consensus on how GMOs should be used. But, as we saw, the controversy surrounding GMOs is more economic, ethical and philosophical than health-related. Eitherway, it is clear that GMOs are and will continue to be a potential great tool to combat global health and nutrition problems in the world, but only if used in a responsible and intelligent manner. 

To have another explanation, in video

• Are GMOs good or bad? Genetic Engineering and our food, by Kurzgesagt – In a Nutshell  https://www.youtube.com/watch?v=7TmcXYp8xu4&t=394s

References

[1] Swiss government approves GMO ban extension, Anand Chandrasekhar (2016) https://www.swissinfo.ch/eng/society/genetically-modified-organisms_government-approves-gmo-ban-extension/42260828

[2] Eurobarometer on Biotechnology (2010) https://ec.europa.eu/commfrontoffice/publicopinion/archives/ebs/ebs_341_en.pdf

[3] Definition: GMOs https://en.wikipedia.org/wiki/Genetically_modified_organism

[4] Definition: selective breeding https://en.wikipedia.org/wiki/Selective_breeding

[5] Definition: spontaneous mutation https://pediaa.com/what-is-the-difference-between-induced-and-spontaneous-mutation/

[6] Definition: recombination https://en.wikipedia.org/wiki/Genetic_recombination

[7] Clementin breeding and origins https://en.wikipedia.org/wiki/Clementine

[8] Evolution of corn bod across history http://forum.woodenboat.com/showthread.php?254584-This-the-week-that-could-break-the-Corn-Belt/page2

[9] Definition: nucleotides https://en.wikipedia.org/wiki/Nucleotide

[10] Do GMOs cause cancer? https://gmoanswers.com/do-gmos-cause-cancer-0

[11] The genetics of fruit flavour preferences, Harry J. Klee  and Denise M. Tieman (2018) https://www.gwern.net/docs/genetics/selection/2018-klee.pdf

[12] Definition: horizontal genetic transfer https://en.wikipedia.org/wiki/Horizontal_gene_transfer

[13] Definition: bacterial resistance https://en.wikipedia.org/wiki/Antimicrobial_resistance

[14] How GMO Technology Saved the Papaya, Elizabeth Held (2016) https://foodinsight.org/how-gmo-technology-saved-the-papaya/

[15] The example of golden rice https://en.wikipedia.org/wiki/Golden_rice

[16] GMOs mosquitoes: what do you need to know https://www.mosquitomagnet.com/articles/gmo-mosquitoes

[17] Introduction to pesticide resistance https://pesticidestewardship.org/resistance/

[18] GMOs could render important antibiotics worthless, Anastasia Bodnar (2010) https://biofortified.org/2010/03/gmos-antibiotics/

[19] Definition: allergy https://en.wikipedia.org/wiki/Allergy

[20] Nothing to sneeze at: the allergies of GMOs, Charles Xum (2015) http://sitn.hms.harvard.edu/flash/2015/allergies-and-gmos/

[21] GMOs safety debate is over, Mark Lynas (2016) https://allianceforscience.cornell.edu/blog/2016/05/gmo-safety-debate-is-over/

[22] Six companies are about to merge into the biggest farm-business oligopoly in history, Chase Purdy (2016) https://qz.com/786382/monsanto-bayer-dupont-dow-chemical-and-syngenta-defend-their-coming-oligopoly-mon-dd-dow-syt/

[23] Consolidation and Competition in the U.S. Seed and Agrochemical Industry (2016) https://www.judiciary.senate.gov/meetings/consolidation-and-competition-in-the-us-seed-and-agrochemical-industry

[24] Inside the Seed Industry, Sara Schafer (2013) https://www.agweb.com/article/inside_the_seed_industry

[25] Meta-Analysis Shows GM Crops Reduce Pesticide Use By 37 Percent, ACSH staff (2014) https://www.acsh.org/news/2014/11/06/meta-analysis-shows-gm-crops-reduce-pesticide-use-37-percent

[26] GMO- A Great Medical Opportunity, Lydia Chain (2014) https://scienceline.org/2014/10/gmo-a-great-medical-opportunity/

[27] The example of insulin https://en.wikipedia.org/wiki/Insulin#Extraction_and_purification

[28] Harnessing bacteria to fight ocean pollution, Adam Zewe (2016) https://www.seas.harvard.edu/news/2016/11/harnessing-bacteria-fight-ocean-pollution

[29] Chemical-Feasting Bacteria Provide New Key for Water Decontamination https://cleanroomconnect.com/chemical-feasting-bacteria-water-decontamination/