Lunchtime! Have you ever given any thought to the food that you eat? Many of the foods that we take for granted come from genetically modified crops. Wheat used to make bread, canola used for cooking, and even tomatoes are examples of GM foods. Foods are often modified to make them stronger, more nutritious, or more resistant to harsh conditions.
You might not be the type to ponder world issues over lunch, but it just so happens that the food you're eating is quite likely at the centre of a controversy that is dividing both science and society. Farmers, scientists, business people, and politicians are all arguing over genetically modified (GM) foods. Some are convinced of the tremendous benefits of GM foods, while others see serious risks. Most are still trying to learn what all the fuss is about.
Why would we want to modify the genetics of a particular food? To make it stronger, more robust, and possibly even resistant to diseases.
The actual science of GM foods is fascinating; you can tweak the genes of an organism to make it taller or tastier or deadlier or more colourful. You can also take genes that do something you want from one organism and combine them with the genes of another organism to make it perform the same function; that function could be anything from producing a spider silk protein to glowing in the dark.
Did You Know?
GM foods are made by adding a gene from one organism into the DNA of another.
Genes are found in most living cells. They provide instruction codes for cells to make proteins or regulate the use of other genes. Cells can do this by translating sections of DNA (deoxyribonucleic acid) molecules into amino acids, which are the building blocks of protein. Several different proteins could be made from the same gene depending on which organism is using it.
NOTE: For more on genes and DNA see: Mutations...What's really behind the X-gene?
Interactions between genes and the proteins they code for are overlapping and complex. It can be difficult to modify one trait in an organism without changing other traits. That's why so many scientists are kept busy scratching their heads over the best ways to modify an organism's genes.
One way to modify the genes of some plants has been to use "invaders" such as viruses or bacteria. In nature, these invaders inject their own genes into a host cell (i.e., plant or animal cell) and force that cell to produce more invaders. Scientists can switch out the invader's own genes and replace it with a gene that they want a plant to use. In this manner, when the invader attacks the host, it inserts these "genes of choice" into the plant cells. The plant cells that start using those genes can be grown into full plants that are ultimately destined for your breakfast, lunch, or dinner.
Scientists also use gene guns to fire gold particles coated with genes into plant cells. These particles inflict damage onto the target cells, but as the cells heal, some start using the new genes. This type of genetic modification, called biolistics, has been used to create Bt-corn which is more toxic to insects.
Bt-corn is a good example of a popular GM food. It's grown mostly in the US, Argentina, and Canada and is used to produce oils, fibres, and livestock feed. Humans don't eat it directly. The gene that makes Bt-corn toxic to insects originally comes from a bacterium called Bacillus thuringiensis, which produces a crystal protein that is toxic to certain corn pests. When these pests eat Bt-corn, they are poisoned and die, which means higher crop yields.
Did You Know?
BT-corn is corn that has been genetically modified to express a gene from a bacterium.
Ecologists are now studying how GM crops, such as Bt-corn, affect ecosystems around them. Many GM crops contain genes that help them survive herbicide spraying. In this way, a herbicide can be used to wipe out all the weeds in a field of GM canola, for example, while leaving the canola intact. However, ecologists and farmers are concerned about potential "super-weeds" that might be created if GM canola breeds with similar plants growing around the field. Weeds with the herbicide resistance gene would be much harder to eliminate!
Many scientists are looking for ways to put GM foods to good use in the future: Crops that can grow in harsh, nutrient-poor environments would help third-world farmers feed their families; bananas could be grown with human vaccines against diseases like Hepatitis B; fish might even be modified to mature more quickly to provide extra food.
So next time you sit down to eat with your friends, ask them what they know about the food they're eating. Challenge yourself to see GM foods from the eyes of a North American farmer, or a biotech CEO, or a struggling mother in a third world country. The more you can learn about GM foods, the more you'll see the controversy and importance of understanding GM foods as they enter the public diet.
References and Cool Sites
Suzuki, D. From Naked Ape to Superspecies (Chapter 5, Unnatural Selections). Allen and Unwin, Sydney. 2004.
Cool genetics resource
GM food technologies
Perspectives on GM foods
Arthur Churchyard is filling his mind with an Arts and Science degree at the University of Guelph. Since he can never decide which science he likes best, he consoles himself by writing about all of them. Arthur interviews Guelph researchers and publishes articles about their work in different Canadian magazines and newspapers as part of a group called Students Promoting Awareness of Research and Knowledge (SPARK).