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Busting the GM myths: a view from Greenpeace

Canola is one of two GM crops approved in Australia. Ngarkat

The Conversation recently published an article looking at the myths about genetic modification. This article is a rejoinder to that piece, and a contribution to the ongoing debate about whether there is any safe way to genetically modify our food.

GM is crude science

Genetic engineering (or genetic modification) inserts DNA (or genes) into the genome of a plant. The genomes of plants and animals are controlled by a complex regulatory network that controls gene expression (the production of proteins). Genetic engineering does not take account of this.

The inserted GM genes operate outside this regulatory network. Because the exact nature of this network is poorly understood, it is not possible to predict the interaction of the inserted genes with the plant’s own genome when the genes are being expressed.

Inserting DNA can cause additional fragments to be inserted and can also delete and rearrange the plant’s own DNA.

Unexpected and unknown fragments of genetic material have been found in commercial GM crops¹ (for example, Roundup Ready soya² and insect resistant maize³, MON810).

As a consequence, GM crops could produce unintended novel proteins, or altered plant proteins. Because most allergens are proteins, this raises concerns about these crops’ potential to cause allergies.

As Richard Richards points out, genetic engineering is not a good way to develop plant varieties with complex traits (such as drought resistance).

This doesn’t mean we can’t develop these types of varieties. Other biotechnologies, such as marker assisted selection (an advanced form of breeding) can be used to develop new varieties, such as drought-resistant rice and wheat.

These technologies use our knowledge of how plant genomes function, but do not result in the deliberate release of a GM plant. Plants developed using this method are already in farmer’s fields.

GM crops do not increase yield and will not solve hunger

The United Nations/World Bank assessment of agriculture was performed by 400 scientists from over 100 countries. They carefully examined whether GM crops increased yields and could not come to a firm conclusion:

“The pool of evidence of the sustainability and productivity of GMOs in different settings is relatively anecdotal, and the findings from different contexts are variable, allowing proponents and critics to hold entrenched positions about their present and potential value.

"Some regions report increases in some crops and positive financial returns have been reported for GM cotton in studies including South Africa, Argentina, China, India and Mexico.

"In contrast, the US and Argentina may have slight yield declines in soybeans, and also for maize in the US⁴”.

The evidence is clear that GM plants are unlikely to play any effective role in increasing food security. In fact, the expense and risk of GM crops could actually decrease food security. GM seeds are subject to patent claims which will indirectly increase the price of food; this will not alleviate poverty or hunger and will pose a threat to food sovereignty.

As the UN Agriculture Assessment states: “In developing countries especially, instruments such as patents may drive up costs, restrict experimentation by the individual farmer or public researcher while also potentially undermining local practices that enhance food security and economic sustainability"⁵.

Food insecurity is related to industrial farming, bad harvests related to climate change, unjust distribution of food, changes in consumption patterns, financial speculation on agricultural commodities and the rush for agrofuels.

This problem is not restricted to the Global South. In 2005, one in 20 Victorians experienced food insecurity.

Solutions to hunger and malnutrition are not easy. But supporting farmers and farm workers in eco-agriculture systems that minimise dependency on external inputs, such as artificial fertilisers and pesticides, is a major option to fight hunger and improve food security worldwide⁶.

GM crops pose risks to the environment

Most GM crops are either insect-resistant (that is, produce their own pesticide), herbicide-tolerant or sometimes both.

The environmental risks of GM insect-resistant crops have been documented in a review of the scientific literature⁷ and are summarised briefly here. Many GM insect-resistant crops produce the same or a similar toxin to GM maize so many of the concerns can, in general, be extrapolated to other GM insect-resistant crops.

GM insect resistant crops are designed to kill specific pests, by exuding a toxin called Bacillus thuringiensis (or Bt).

This Bt is different from the bacterial sprays used in conventional and organic agriculture: it is less specific to the organisms it can affect. For example, GM insect-resistant crops may be toxic to "non-target” organisms, such as butterflies. Long-term exposure to pollen from GM insect-resistant maize causes a decreased survival rate in monarch butterfly larvae⁸.

GM insect-resistant crops can be toxic to other, beneficial insects which are important in the natural control of maize pests, such as green lacewings.

Studies have shown that other, new pest insects are filling the void left by the absence of the specific insect pests controlled Bt crops target⁹. This leads to the spraying of additional pesticides with additional costs to both farmers and the environment.

GM herbicide-tolerant crops are generally associated with one of two herbicides: glyphosate (sold as Roundup), associated with GM Roundup Ready crops, or glufosinate, associated with GM Liberty Link crops. Both these herbicides raise concerns but, in terms of environmental effects, most studies have focussed on glyphosate (or Roundup).

In the past 10-15 years, many new studies suggest that Monsanto’s Roundup is far less environmentally benign than previously thought. These studies are the subject of a recent review¹⁰ but are summarised briefly here.

There are concerns Roundup (or glyphosate) is toxic to aquatic biodiversity¹¹, such as frog larvae (tadpoles).

Glyphosate applications are associated with nutrient (nitrogen and manganese) deficiencies in GM Roundup Ready soya, thought to be induced by its effects on soil microorganisms¹².

Evolution of weed resistance to Roundup is now well-documented as a serious problem where Roundup Ready crops are grown on a large scale. Increasing amounts of herbicide have to be used to control these weeds, or else additional herbicides have to be used to supplement Roundup. This implies an increased toxic burden on the environment and people.

We do not know if GM foods are safe to eat

Many GM crops end up in food for humans and animals. In Australia, only two GM crops are cultivated – canola and cotton – but many are approved for food imports.

There are two ways in which genetic engineering may affect food safety:

  • Gene disruption or instability may lead to new toxins being produced.
  • The new protein produced by the foreign gene may cause allergies or toxicity.

Because GM crops are prone to unexpected and unpredictable effects, the evaluation of food safety requires looking for unexpected and unpredictable effects. This is extremely difficult, if not impossible. Therefore, all current testing regimes for GM foodstuffs around the world are inadequate.

National inadequacies also exist. A recent report of the Australian Auditor General questioned whether Food Standards Australia New Zealand (FSANZ) gets sufficient information from applicants to be an effective regulator.

The Auditor found that FSANZ has no procedure for ensuring the data provided by corporate applicants is actually correct and complete. They found gaps in supporting data and evidence that some applications were approved¹³, despite these gaps.

In 2005, the development of an Australian GM pea was dramatically stopped because a study found serious health impacts in mice¹⁴. Small changes in the structure of the GM protein were found to unexpectedly cause allergenic reactions in mice.

The incident sent shockwaves around the world. People wanted to know whether this toxicity would have been detected in routine testing to evaluate GM food safety.

As the editor of New Scientist said¹⁵:

“The important question is whether national regulatory authorities would have spotted the allergy. In Australia, where the research was done, the answer is no. Although researchers ended the project voluntarily when they discovered the allergic reactions, the tests they did are not mandatory.”

We simply do not know if GM crops are safe for animal or human consumption.


1) Windels, P. et al. 2001. European Food Research Technology 213:107-112

2) Rang, A. et al 2004. European Food Research Technology 220: 438-443

3) Hernandez, M. et al. 2003. Transgenic Research 12: 179–189

4) IAASTD. 2009. Agriculture at a Crossroads - Synthesis report.

5) IAASTD. 2009. Agriculture at a Crossroads - Synthesis report.

6) Nellemann, C. et al.2009. The Environmental Food Crisis.

7) Cotter, J. 2009. GM insect-resistant (Bt) maize in Europe: a growing threat to wildlife and agriculture

8) Dively, Galen P. et al. 2004. Entomological Society of America 33: 1116-25.

9) Wang, S. et al 2008. Int J Biotechnology 10: 113-21.

10) Riley, P. et al. 2011. Herbicide Tolerance and GM Crops.

11) Relyea, Rick A.. 2005. Ecological Applications 15:1118–1124

12) Kremer, R.J. and Means, N.E.. 2009. European Journal of Agronomy 31: 153-161.

13) ANAO. 2010. Food Standards Australia New Zealand.

14) Prescott, Vanessa E. et al. 2005. J. Agric. Food Chem. 53: 9023–9030.

15) Editorial. 2005. New Scientist 2527.

Greenpeace campaigns to prevent the deliberate release of genetically modified (GM) or genetically engineered (GE) organisms into the environment. GM organisms (plants, animals, micro-organisms) are living organisms that can multiply and cross-breed and pose a threat of irreversible damage to biodiversity and ecosystems. The safety, long term, of GM food for humans and feed for animals is unknown.

Dr Cotter is visiting Australia from October 16-26 to highlight concerns over the safety of GM wheat.

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