THE SYNTHETIC BIOLOGY PROJECT
GENETICALLY MODIFIED FOODS 101
What are GMOs and GM foods?
GMOs stand for “genetically modified organisms”, meaning that they are plants, animals, microbes that have had their DNA modified using genetic engineering techniques. GMOs have a wide variety of uses, including in agriculture, research, and medicine. Some GMOs are used to produce food for human consumption. These are known as GM (genetically modified) foods! However, there are many misconceptions surrounding GMOs in the public eye, with 31% of Australians seeing GM foods as unsafe and another 37% believing they do not have enough information to say [1].
A trip down history lane...
Traditional methods of genetic manipulation have been used in farming practices for thousands of years. This is called “selective breeding” or “cross-breeding", where specific plants or animals are chosen to be bred together to produce offspring with certain desirable traits [2, 3].
Scientists began investigating DNA and genetic modification in the early 20th century. Scientists discovered that DNA could be modified to produce different traits and proteins, leading to modern day genetic engineering. In 1973, scientists produced the first functional recombinant DNA. A plasmid, aka a small fragment of DNA, was recombined from two bacterial sources and inserted into a different species of bacteria. Scientists made the first GMO product for human use in 1982, creating genetically modified bacteria that could produce human insulin, which could be used to treat diabetes [2, 3, 4, 5].
The first commercially available GM food was the Flavr Savr tomato created in 1994, which was genetically engineered to have a gene that slows down pectin degradation [6]. This meant the tomato could be left to ripen for longer on the vine and had a longer shelf life. These tomatoes were advertised as genetically modified and even had information brochures included with purchase. However, due to production costs and issues with handling and transport, the tomato was discontinued after 3 years.
Today, there are around 80 different GM food crops grown around the world, mainly canola, soybean, corn and cotton, however regulation differs in every country [7].
How does genetic modification work?
Previously, in the 1930s, scientists had used chemicals or radiation to randomly induce new traits in plants, creating thousands of new variants. However today’s methods of genetic modification are much more precise, usually altering select, target genes [3, 8, 9].
Usually, a single gene is added from another species, for example Bt corn, which has a protein from a natural soil bacterium, Bacillus Thuringiensis. This protein helps make the corn resistant to insects, reducing the use of chemical pesticides and insecticides, and also produces a higher yield of corn [10].
Specific DNA fragments are delivered into target cells using a microparticle bombardment method or a controlled bacterial vehicle. The recent development of a genome editing technique, called CRISPR/Cas9, allows for direct edits of an organism’s genes [8].
Today, scientists are working on GMOs to produce solutions to address many current agricultural, health and environmental challenges. Examples of GM crops include herbicide and insect resistant crops, "Golden Rice" fortified with vitamins, papaya engineered to be resistant to plant viruses, and many more.
Are GMOs safe? What are the benefits and risks of GMOs?
Research and extensive reviews of GM foods available in Australia have demonstrated that they are safe to consume and no less nutritious than their conventional equivalents. However, it is always important to understand and evaluate both benefits and risks of using GMOs [3, 11, 12].
Benefits:
The main motivation for GMO research is to provide solutions to a changing planet with a growing population and limited available land for farming.
Many GM crops are designed so that more crops can be grown, on less land, with less pesticide/herbicide usage. By focusing on improving crop genetics and yield, this could help provide solutions to ensure there is enough food to feed the world’s population, as well as improving nutrition and processing of these foods; and generating more profit for farmers .
Some crops are purposely engineered to enrich specific nutrients such as vitamins, unsaturated fatty acids, fiber and probiotics, for therapeutic/health reasons [8]. In some cases, crops are engineered to be resistant to plant viruses, to ensure the crops are not wiped out by those deadly viruses [12].
Risks:
The main concerns of using GM foods is in regards to health and ecological risks. GM foods need to be tested for any potential toxic or allergic effects, which could be caused from the introduced product of the newly inserted gene. There could also be a risk of disrupting the original genetic information in the organism being modified.
There are concerns that GM crops could interfere with the food web, for example if a crop was engineered to be resistant to a major pest, it could lead to an increase in other minor pests. Selection of resistance is another issue - weeds/insects could evolve to be resistant against GM crops, making them useless.
There could also be an increased resistance to antibiotics used in the process of creating GM crops. Although the use of antibiotics is being slowly replaced by other methods, antibiotic resistance is a major health concern of the modern day [8].
What GM crops and foods are there in Australia?
At the moment, only four GM food crops have been approved to be grown in Australia, which are canola, cotton, Indian mustard and safflower [7]. Others are currently undergoing field trials, including GM banana, wheat, barley, ryegrass, and sugarcane. Majority of approved GM crops in Australia are gene-edited to be herbicide, insect/pest or drought resistant, or to produce crops with improved levels of a specific oil or protein. Some of these crops are grown to make cooking oil for food consumption, however a larger amount is grown to be used for textiles, livestock feed and industrial uses.
There are also some GM ingredients that aren’t grown in Australia, but can be found in food products for sale in Australia. The most common GM ingredients include imported GM soya, corn and sugar beet, as well as cottonseed oil [3]. Although some exist around the world, currently, there are no fresh GM fruits or vegetables that are being sold in Australia.
Are GM foods regulated?
All GM foods available for purchase in Australia are under the Australia New Zealand Food Standards Code. Before being approved, GM foods and ingredients are assessed to ensure they are safe. GM foods are assessed for their nutritional content, any potential toxicity/allergenicity, effects of genetic changes and compared to their conventional counterpart [3, 11].
All GM foods and ingredients you would find in a supermarket are required to labelled by law. Food intended for immediate consumption in restaurants/cafes do not have GM labelling requirements, however you can ask the food business for information [11].
Some food manufacturers include "GMO-free" labelling on their products, however, this has been criticised by some as being misleading and unnecessary in driving fear of GMOs in consumers [13, 14].
Have more questions? Leave a comment below!
References:
1. Kennedy B. Many publics around world doubt safety of Genetically Modified Foods [Internet]. Pew Research Center; 2020 [cited 2023 Aug 17]. Available from: https://www.pewresearch.org/short-reads/2020/11/11/many-publics-around-world-doubt-safety-of-genetically-modified-foods/
2. Eibl R, Senn Y, Gubser G, Jossen V, van den Bos C, Eibl D. Cellular agriculture: Opportunities and challenges. Annual Review of Food Science and Technology. 2021;12(1):51–73. doi:10.1146/annurev-food-063020-123940
3. Department of Health & Human Services. Food - genetically modified (GM) [Internet]. Department of Health & Human Services; 2021 [cited 2023 Aug 17]. Available from: https://www.betterhealth.vic.gov.au/health/healthyliving/food-genetically-modified-gm/
4. Center for Food Safety and Applied Nutrition. Science and History of GMOs and Other Food Modification Processes [Internet]. FDA; 2023 [cited 2023 Aug 17]. Available from: https://www.fda.gov/food/agricultural-biotechnology/science-and-history-gmos-and-other-food-modification-processes
5. Rangel G. From Corgis to Corn: A Brief Look at the Long History of GMO Technology [Internet]. SITNFlash; 2015 [cited 2023 Aug 17]. Available from: https://sitn.hms.harvard.edu/flash/2015/from-corgis-to-corn-a-brief-look-at-the-long-history-of-gmo-technology/
6. Kramer MG, Redenbaugh K. Commercialization of a tomato with an antisense polygalacturonase gene: The FLAVR savrTM tomato story. Euphytica. 1994;79(3):293–7. doi:10.1007/bf00022530
7. Office of the Gene Technology Regulator. Genetically modified (GM) crops in Australia [Internet]. Office of the Gene Technology Regulator; 2023 [cited 2023 Aug 17]. Available from: https://www.ogtr.gov.au/resources/publications/genetically-modified-gm-crops-australia
8. Zhang C, Wohlhueter R, Zhang H. Genetically Modified Foods: A Critical Review of their promise and Problems. Food Science and Human Wellness. 2016;5(3):116–23. doi:10.1016/j.fshw.2016.04.002
9. Turnbull C, Lillemo M, Hvoslef-Eide TA. Global regulation of genetically modified crops amid the gene edited crop boom – a review. Frontiers in Plant Science. 2021;12. doi:10.3389/fpls.2021.630396
10. Palma L, Muñoz D, Berry C, Murillo J, Caballero P. Bacillus thuringiensis toxins: An overview of their biocidal activity. Toxins. 2014;6(12):3296–325. doi:10.3390/toxins6123296
11. Food Standards Australia & New Zealand. Safety assessments of GM foods [Internet]. Food Standards Australia & New Zealand; 2021 [cited 2023 Aug 17]. Available from: https://www.foodstandards.gov.au/consumer/gmfood/safety/Pages/default.aspx
12. Davidson SN. Forbidden fruit: Transgenic papaya in Thailand. Plant Physiology. 2008;147(2):487–93. doi:10.1104/pp.108.116913
13. Kim Y, Kim S, Arora N. GMO labeling policy and Consumer Choice. Journal of Marketing. 2022;86(3):21–39. doi:10.1177/00222429211064901
14. Redden R. Genetic modification for agriculture—proposed revision of GMO Regulation in Australia. Plants. 2021;10(4):747. doi:10.3390/plants10040747
