Perspectives on GMOs

Chris Johansen

Greens Leader Richard Di Natale recently expressed his opinion that not everything about genetically modified organisms (GMOs) should be considered as a no-go zone. Being a medical practitioner he opined "The literature so far, on the issue of human health, hasn't produced evidence of widespread and significant health harms". He further expressed that “he did not have a philosophical or ideological opposition to the technology itself”, and that "the concerns are less around human health and much more around the application of the technology when it comes to giving farmers choice, ensuring that farmers are able to produce a non-GM product if they choose, making sure we don't use this technology simply to drive up the use of more herbicides and pesticides, which is not good land management”.

And how does this match with Australian Greens policy on GMO, which is:

The Australian Greens believe that:

1. Genetically modified organisms (GMOs), their products, and the chemicals used to manage them may pose significant risks to natural and agricultural ecosystems.
2. GMOs have not been proven safe to human health.
3. Scientific evidence produced independently from the developers and proponents of the GMO must be undertaken and form the basis for assessing and licensing of GMOs. GMO assessments must be broad, independent and scientifically robust.
4. The precautionary principle must be applied to the production and use of GMOs.
5. Living organisms such as plants, animals and micro-organisms are not inventions. Patents on life are unethical and against the public interest.
6. The Australian government must prohibit the use of 'terminator' technologies (Gene Use Restriction) that prevent seeds from germinating when planted.
7. Farmers and consumers have a right to grow and consume non-GMO foods.
8. Everyone has a right to know if foods contain any ingredients made using GM techniques, through the comprehensive labelling of those products.

The only possible deviations of RDNs views from the above policy would relate to points 2 and 4. Interpretation of point 2 depends on how “safe” is defined. Nothing ingested can be proven to be 100% safe, only a certain level of risk assigned. And his point was that any GMO foods are yet to be proven “unsafe”. Similar interpretation of point 4 depends on the level of caution considered necessary – ultimately there is some level of risk in any action.

It is not my usual habit to unflinchingly agree with my betters/seniors/leaders but in this case I share Richards perspective – that we need a rational, science based view on GMOs, like we claim to have on climate science. Seems like an appropriate time for me to give my views on GMOs as applied to crop plants, based on my background in plant physiology.

Firstly, to define GMOs: GMOs are organisms whose genetic composition has been artificially altered by direct insertion of exotic genes (from another species or synthetic constructs) or deletion of existing genes. Exotic genes may be inserted into cells by infection with Agrobacterium carrying those genes, physically shooting genes into cells (gene gun or biolistics) or giving an electric shock which increases membrane permeability allowing gene entry (electroporation).

To me, these are just additional methods of genetic manipulation of plants (and domestic animals and bacteria), realizing that humans have been genetically manipulating plants for at least 10,000 years. Initially, hunters and gatherers collected seed, or other propagules, of desirable plant types and planted them thus altering the genetic composition of natural populations to favour those desired characteristics. Then, humans learned how to enhance this process by deliberate cross pollination of desirable parents, leading to conventional plant breeding, upon which most of the plant food we now eat is based. And over the last century plant breeding has been enhanced by such methods as inducing mutations (by radiation or chemicals) and embryo rescue (facilitating inter-species crosses). Products of these latter methods are not considered as GMOs.

Further, I have no problem with insertion of genes from other species or life forms as genetic material of all life forms has the same basic composition. All DNA (deoxyribonucleic acid) is composed of various combinations of the nucleobases cytosine, guanine, adenine and thymine, bound together by the monosaccharide sugar deoxyribose and phosphate groups. In fact, Im quite happy to share my basic genetic composition with an earthworm, which can eat soil whereas I cant, or a green plant, which can directly convert sunlight into energy whereas I cant.

Thus, like RDN, I have no ethical, philosophical or ideological problems with GM technology itself.

Over the years I have only cursorily followed the scientific literature on safety of GMO foods but have not come across anything too alarming, in relation to all of the other food hazards, particularly pesticide residues. The major study raising concern is that of Gilles-Eric Séralini and colleagues who claimed that long term feeding of GM corn resistant to herbicide caused cancer in rats. But diverse peers, who are specialists in the field, have criticised the methodology followed and thus do not accept their conclusions. Actually, from a physiological and biochemical viewpoint I cant quite see how insertion of genes to enhance herbicide or drought tolerance or improve plant food quality characters (e.g. colour, mineral and vitamin fortification) would necessarily result in production of harmful by-products.

However, I do see how insertion of genes to provide resistance to insects or fungal disease, through production of internal plant toxins, could also be harmful to humans. Thus I would want to see rigorous animal toxicity tests for such GM plants. But, on the other hand, I see such GM-based toxins as no greater risk than the synthetic insecticides and fungicides applied to most crops whose products we consume. And not to mention the multitude of chemical food additives, to enhance colour, taste, shelf-life, etc., found in most packets on supermarket shelves. Application of a strict precautionary principle in the face of all of these potential hazards would, Im afraid, leave me with little to eat.

Thus, also like RDN, I do not have great concerns about human health consequences of consuming products of GM crops, in relation to all of the other potential hazards of consuming food.

Nevertheless, however, I do confess to a personal bias against GM crops, probably based on a bitter experience of some 25 years ago. Then research funding was redirected from the physiology/agronomy/plant breeding projects I was engaged in to satiate the hype being generated that all of our problems could be rapidly solved through application of GM technology. Long story short, and another “told-you-so” moment for me, nothing of any practical importance has resulted from the GM projects established then, just a lot of scientific publications.

My main concerns with the application of GM technology, which mainly relate to the effectiveness of its use, can be summarized (very briefly; to fully qualify these arguments I would need a lot of space!) as follows:

• The major application of GM technology for crops has been in developing herbicide (mainly glyphosate) resistance in crop plants so that herbicides can be sprayed at will to control weeds without harming the crop. This technique has been employed by multinational chemical companies, such as Monsanto, for the prime purpose of selling more chemical herbicide. However, this has had the effect of creating herbicide resistant weeds, which gets us back to square one with weed management. Not to mention the explosion in use of glyphosate, which the World Health Organization (WHO) has classified as carcinogenic.
• The second widest application of crop GM technology is enhancement of insect resistance, mainly in cotton and corn. Again, insects rapidly develop resistance to these plant toxins unless refugia strategies are strictly followed – growing non-GM plants nearby where the as-yet non-resistant insects can happily breed and thus dilute out resistant strains. Other problems include the killing of non-target, and perhaps beneficial, insects.
• Claims of being able to improve characters determined by multiple genes, like yield potential and drought resistance. Due to the complexity of physiological feedback mechanisms and interactions this is a step too far with current knowhow. Conventional plant breeding still holds most promise for this purpose into the medium term future.
• Use in biofortification – i.e. increasing concentrations of essential minerals and vitamins in crop produce (e.g. “golden rice” which is Vitamin A enhanced). There are more effective ways of overcoming mineral and vitamin deficiencies in humans, such as distribution of pills and diet diversification.
• Cross contamination of GM genes into land where farmers want to grow non-GM crops (e.g. the Steve Marsh case) or non-GM grain silos. This can occur through accidental physical dispersal of GM seeds or through GM pollen from outcrossing crops, such as corn and canola. There should be strong government regulation to clearly separate GM and non-GM food, so that farmers can retain their free choice of what they grow and consumers their free choice of what they eat.
• Monopolistic control by multinationals of what farmers can grow and potentially legally binding them into debt, should crops fail due to adverse weather events, etc.

I could go on but, in summary, I acknowledge GM as a potential tool for crop improvement but not a very useful one in relation to the alternatives available. A bit like the touted benefits of mutation breeding in the 50s and 60s, but this technology also largely failed to deliver. And of GM foods that are available, I dont have great concerns about consuming them, in relation to all of the other food hazards. Despite lack of labelling, I know I do consume them as any food with soybean and corn ingredients derived from the Americas is likely to come from GM soybean and corn crops.

Photo: Canola fields in WA DAFWA