Part 1 of this article, published last week, reflected on the complex and confusing nature of the public debate about genetically modified organisms (GMOs). We saw how the reasons behind the application of this technology may not be realised or fully realised in actuality. We examined research which indicates that GM crops have not been proven to be safe for consumption, and indeed may be harmful to living organisms…

Mechanisms exist to explain how such damage could occur. One reason GM crops are usually considered safe for human consumption is that our intestines are not supposed to be permeable to any but the smallest molecules. If the Bt toxin, glyphosate and altered genes cannot get into the human body then maybe they cannot do any damage. However, we now know that this assumption is incorrect on a number of levels. Glyphosate is a powerful herbicide, but it is also an antibiotic. It reduces the beneficial gut microbiota and allows a different microbiota to establish itself which leads to intestinal permeability (nicknamed ‘leaky gut syndrome’) and inflammation. Likewise, the Bt toxin has been demonstrated to increase intestinal permeability (Mesnage et al, 2013). This ‘leaky gut syndrome’ allows entire protein molecules and DNA fragments to enter the bloodstream, and is thought to set the stage for many inflammatory and auto-immune diseases (such as most of the diseases mentioned in Part 1 of this article).  Spisak et al (2013) report that in some blood samples taken from patients, the concentration of plant DNA is higher than that of human DNA. Obviously, a lot of big molecules are sneaking their way into our bloodstream from our gut. One implication is that crop DNA may be able to ‘donate’ their transgenes to the bacteria in our gut and in our bodies.

When GMOs are created in the laboratory, genes for antibiotic resistance are frequently used as marker genes for the altered cells. The worldwide problem of antibiotic resistant organisms calls into question the safety of this practice and the resulting genetic material. Sirinathsinghji (2013) reported on a study detailing the presence of antibiotic resistant wild bacteria in 6 major rivers in China. The gene responsible for the antibiotic resistance is used as a marker gene in GM crops, and Sirinathsinghji postulated that the altered genes had naturally transferred from GM crops to the wild bacteria. As we’ll see later, that is likely the case. The study surmised that the gene was responsible for the widespread occurrence of antibiotic resistant bacteria in the Chinese population – a major health concern.

So is the genetic modification of crops an exact science? Does it produce stable products that can be contained? Can living organisms be adequately protected from harm? The answer would appear to be ‘no’ to all three questions. Mankind has a limited, albeit increasing, knowledge of the science of genetics and the new science of epigenetics (both heritable and non-heritable changes in gene expression and activity). We are only just starting to learn how changes in our genotype (DNA) lead to changes in our phenotype (our traits) and how our phenotype (and even our genotype) can be modified by epigenetics. Lin et al (2014) discovered that off-target effects are common due to the imprecise nature of gene manipulation, and these off-target changes are not assessed for safety. Unintended consequences can occur that may or may not be harmful, and our regulatory agencies do not assess or manage those risks correctly (Heinemann et al, 2013). An example of this is the L-Tryptophan toxin already mentioned.

GM crops under cultivation often cannot be contained to a particular location. Bauer-Panskus et al (2013) detail research on cases where GM crops spread in an uncontrolled (i.e. uncultivated) fashion. Important cases have involved bentgrass, canola and cotton. Grasses, such as bentgrass, corn and rice, are wind pollinated and more likely to invade other areas and persist in the environment. This appears more likely if the species has a wild relative that will cross with it. Price & Cotter (2014) report on an analysis of the GM Contamination Register in which contamination incidents have been recorded from 1997 to 2013. GM rice accounts for the highest number of incidents – and there is no commercial GM rice growing anywhere in the world – followed by maize, soy and canola. Of course, GM pollen doesn’t just blow in the wind – it travels by other vectors as well. Villanueva-Gutierrez et al (2014) delineate the contamination of honey by GM soybean pollen on the Yucatan peninsula in Mexico. And modified genes themselves can escape into the wild, with or without pollen.

Overballe-Petersen et al (2013) presents interesting research on bacterial transformation and the acquisition of genetic material by wild bacteria. DNA and DNA fragments exist everywhere in the environment as a natural by-product of decomposition processes. These molecules persist in the environment, albeit in a fragmented and damaged state, if they are not decomposed further – DNA fragments have been found that are 500,000 years old.  Wild bacteria freely exchange DNA and DNA fragments in the environment. One implication is that transgenes can be released into the environment by the process of plant decomposition and then be incorporated into a wild bacteria. We already saw a possible consequence of this in the wild antibiotic-resistant bacteria in Chinese rivers.

It would be logical that the onus would be on biotechnology companies to prove the safety of GM crops in a completely transparent fashion, but that does not seem to be the case. Standards for GM crop regulation are not stringent in many countries, and they are not consistent from country to country.  GM Freeze (2014) reports on moves by the European Union that would consider individual countries to be responsible for authorising the use of GM crops within their borders. The most serious problem with this approach is that pollen and gene fragments do not understand the concept of ‘borders’, and cross-contamination will make a mockery of a country’s attempt to remain GM-free. And research, especially research carried out with corporate funding and considered commercially sensitive, is not always transparent. Finally, consumers often don’t have the ability to opt out of purchasing foods made from GMO crops, because they may not be labelled as such.

A reason sometimes given for slack regulatory processes is that GM crops are ‘substantially equivalent” to non-GM crops. This concept of substantial equivalence must be abandoned. A study done with GM and non-GM maize grown in field conditions in Brazil determined that proteins may be expressed differently depending on the type of maize, as well as the particular cultural techniques used (Agapito-Tenfen et al, 2013). These proteins were generally involved with carbohydrate metabolism, genetic information processing, stress response and energy metabolism. And we’ve already seen that nutrients can be vastly different between GM and non-GM crops (Abdo et al, 2013).

The final question to ask is whether better alternatives to GM crops are available. Is there a better way to provide increased crop productivity, better nutrition, better taste and storage capabilities and decreased need for pesticides? The answer is absolutely yes.

  • Small farms, not large farms, feed the world (GRAIN, 2014). We need to return to small, diverse family farms whose farmers will act as stewards for their land. Small farms are more productive and less wasteful of water.
  • Agroecology is the only viable future for farming (De Shutter, 2010). It provides for sustainable, highly productive food systems that support an equitable right to adequate food for all.
  • Traditional selective breeding techniques have produced increased nutrition, better taste, better storage capabilities and pest and disease resistance in crops (Gurian-Sherman, 2009).
  • Traditional selective breeding techniques can be enhanced using genomics – knowledge of a plant’s full genome. In this way, varieties with particular traits can be targeted better for breeding programs.
  • We need to redefine yield and productivity to reflect the lessons learned in permaculture. A diverse polycultural farm will always yield better than a monoculture, if yield is defined as the sum of all products and services of all the elements. A healthy planet is one of the yields we should be aiming for.

Many countries, states, cities and regions have declared themselves to be GM free or partially GM free (where they ban specific crops but not others). This ban may only be applied to commercial production or it may apply to experimental trials as well. Other areas have applied moratoria instead of an outright ban. The Swiss moratorium on the cultivation of GM crops is one of the strongest. Most countries in the EU maintain a partial ban (Monsanto’s GM maize appears to be the most popular variety to ban). New Zealand is free of commercial GM crops but a number are currently under trial. Tasmania has recently extended its moratorium on GM crops and animals. These snippets of sanity are great news, but as discussed earlier – pollen and transgenes flow across borders.

The take-home message? The public debate about the pros and cons of GMOs is a difficult one, full of complexity and angst. People are likely to have a world view and then, thanks to cognitive dissonance, look for arguments that reinforce their world view and ignore arguments that challenge it. This is the nature of humans. But the stakes in this game are very high, and there is no substitute for doing your own research. In the meantime, eat organic fruit and vegetables. Stay away from processed foods, particularly if they contain grains. If you eat meat, choose grass-fed, ethically raised meat and wild fish if it’s sustainably harvested. If you eat grains, make sure they aren’t genetically modified. Don’t be ignorant, because it certainly isn’t bliss in this case. This strategy should keep you well away from GM crops and their associated pesticides and toxins. Advocate for better GM regulation, as well as organic, regenerative agriculture.


References for Part 2

ABDO, E M, BARBARY, O M AND SHALTOUT, O E 2013. Chemical Analysis of BT corn “Mon-810: Ajeeb-YG®” and its counterpart non-Bt corn “Ajeeb”. IOSR Journal of Applied Chemistry, 4(1), 55-60.

AGAPITO-TENFEN, S, GUERRA, M, WIKMARK, O-G & NODARI, R 2013. Comparative proteomic analysis of genetically modified maize grown under different agroecosystems conditions in Brazil. Proteome Science, 11(1), 46.

BAUER-PANSKUS, A, BRECKLING, B, HAMBERGER, S & THEN, C 2013. Cultivation-independent establishment of genetically engineered plants in natural populations: current evidence and implications for EU regulation. Environmental Sciences Europe, 25(1), 1-9.

DE SCHUTTER, O 2010. Report submitted by the special rapporteur on the right to food. United Nations Human Rights Council.

GM FREEZE 2014. Contamination Matters – Why GM crops can’t be managed at a national level. GM Freeze. Available:

GRAIN 2014. Hungry for land: Small farmers feed the world with less than a quarter of all farmland. Available:

GURIAN-SHERMAN, D 2009. Failure to yield: Evaluating the performance of genetically engineered crops. Union of Concerned Scientists. Available:

HEINEMANN, J A, AGAPITO-TENFEN, S Z & CARMAN, J A 2013. A comparative evaluation of the regulation of GM crops or products containing dsRNA and suggested improvements to risk assessments. Environment International, 55, 43-55.

LIN, Y, CRADICK, T J, BROWN, M T, DESHMUKH, H, RANJAN, P, SARODE, N, WILE, B M, VERTINO, P M, STEWART, F J & BAO, G 2014. CRISPR/Cas9 systems have off-target activity with insertions or deletions between target DNA and guide RNA sequences. Nucleic Acids Research, 42(11), 7473-7485.

MESNAGE, R, CLAIR, E, GRESS, S, THEN, C, SZÉKÁCS, A & SÉRALINI, G-E 2013. Cytotoxicity on human cells of Cry1Ab and Cry1Ac Bt insecticidal toxins alone or with a glyphosate-based herbicide. Journal of Applied Toxicology, 33(7), 695-699.

OVERBALLE-PETERSEN, S, HARMS, K, ORLANDO, L A A, MAYAR, J V M, RASMUSSEN, S, DAHL, T W, ROSING, M T, POOLE, A M, SICHERITZ-PONTEN, T, BRUNAK, S, INSELMANN, S, DE VRIES, J, WACKERNAGEL, W, PYBUS, O G, NIELSEN, R, JOHNSEN, P J, NIELSEN, K M & WILLERSLEV, E 2013. Bacterial natural transformation by highly fragmented and damaged DNA. Proceedings of the National Academy of Sciences, 110(49), 19860-19865.

PEDERSON, I B 2014. Changing from GMO to Non-GMO Natural Soy, Experiences from Denmark. Available:

PRICE, B & COTTER, J 2014. The GM Contamination Register: a review of recorded contamination incidents associated with genetically modified organisms (GMOs), 1997–2013. International Journal of Food Contamination, 1(1), 1-13.

SIRINATHSINGHJI, E 2013. GM Antibiotic Resistance in China’s Rivers. ISIS. Available:


VILLANUEVA-GUTIERREZ, R, ECHAZARRETA-GONZALEZ, C, ROUBIK, D W & MOGUEL-ORDONEZ, Y B 2014. Transgenic soybean pollen (Glycine max L.) in honey from the Yucatan peninsula, Mexico. Sci. Rep., 4.

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