Above: Image © istockphoto.com/vreemous
Did you know that your family dog is a genetically modified organism? It’s true. The dog breeds we recognize today were created through selective breeding. In other words, dogs have been genetically modified to make them better companions and workers. In fact, our ancestors began tinkering with the genetic makeup of different species like sheep, cereal crops, and apple trees long before genes were even discovered. Thanks to their efforts, you can enjoy the warmth of your wool jacket, the taste of your breakfast cereal, and the juiciness of your favourite apple variety.
Did You Know? The first genetically-engineered organism was a bacterium created by Stanley Cohen and Herbert Boyer in 1973.Selective breeding is very different from a much newer type of genetic modification: genetic engineering (GE). In recent years, GE has inspired a lot of debate, as potential benefits are weighed against potential dangers and ethical concerns.
Over the course of the last 150 years, researchers have learned that genes are responsible for almost all inheritable traits. They have also figured out how genes work. A huge step forward was the discovery of DNA, which contains the genetic code for all forms of life, including the traits we favour in dogs, sheep, cereals, and apple trees.
The discovery of DNA is what made GE possible. Instead of selectively breeding over multiple generations, researchers can now directly combine and manipulate an organism’s genes to give it more desirable traits. This makes it possible to alter species a lot faster and much more dramatically.
Many microorganisms, plants, and animals have already been genetically engineered to create cheaper, more nutritious foods and more effective medical treatments. Here are just a few examples of GE’s huge potential:
Golden Rice is a genetically-engineered variety of rice supplemented with vitamin A. It is useful in preventing and treating illnesses linked to vitamin A deficiency, including blindness. The vaccine against the human hepatitis B virus made from a genetically-engineered strain of yeast. Bacteria that live in mosquito’s guts have been engineered to destroy the malaria parasite, which could help eradicate the disease. Leukemia patients may soon be treated with altered versions their own immune cells, which have been genetically engineered to enhance their cancer-fighting skills. Genetically-engineered microbes and plants may one day help decontaminate soil and water.
However, the potential benefits of GE need to be weighed against risks and ethical considerations. In particular, what are the dangers associated with altering the genetic makeup of different species? And just because they can, do humans have the right to do it? Indeed, this technology could pose a variety of risks to human health and the environment.
Did You Know? A new field of genetic engineering – synthetic biology – aims to streamline the production of live machines.In the short term, GE products could cause allergies and other toxic effects. A first warning came when a 1999 laboratory study reported that pollen from Bt Corn—one of the first commercial GE crops—was toxic to monarch butterfly larvae. Although more recent studies have helped rehabilitate the reputation of Bt Corn, the study helped make it mandatory for all GE food products to be tested for allergic and other toxic effects before they can be sold to consumers.
There are also fears that, over time, modified genes may be transferred from GE foods to human cells or to bacteria that live in the human gut. Although this is theoretically possible and potentially hazardous, such transfers have never been observed. On the other hand, foreign gene transfers have been observed in plants. For example, there is evidence that different GE canola plants swap genes in the field.
Other undesirable side-effects, such as the emergence of hard-to-control pests, are also possible. This can occur when farmers grow only pesticide-producing GE crops, or when pesticides are used in excess because of GE crops being pesticide-resistant.
Fortunately, safety concerns have not fallen on deaf ears. Government agencies now oversee how GE products are developed and used. And many researchers have made food and environmental safety a priority. For example, a new generation of GE crops is being developed by only manipulating the plants’ native genes and without introducing any foreign genes. Future GE crops are also being designed to repel pests in ways that will make emergence of pesticide resistance unlikely.
As advances in GE continue, so does the debate about the safety of GE products. And even if GE were proven to be completely safe, many would still take issue with the idea that human beings should be engineering life. Clearly, GE is a double-edged sword that must be handled responsibly and with care.
GM? GE? Gee Whiz! (Stefanie Vogt, CurioCity E-Zine)
Applications of Genetic Engineering (Boundless) DuPont-Dow Corn Defeated by Armyworms in Florida: Study (Jack Kaskey, Bloomberg Sustainability) First recombinant DNA (SNA Learning Center, Cold Spring Harbor Laboratory) Gene Therapy Shows Promise Against Leukemia (WebMD News) Genetically Engineered Bacteria Prevent Mosquitoes from Transmitting Malaria (Bloomberg School of Public Health, Johns Hopkins University) Genetically Modified Crop on the Loose and Evolving in U.S. Midwest (David Biello, Scientific American) Golden Rice (C. Kameswara Rao, Foundation for Biotechnology Awareness and Education) How Microbes Clean Up our Environmental Messes (Mary Beth Griggs, Popular Mechanics) Pros of Genetic Engineering: Why ‘Playing God’ Could Help The Human Race (Rayshell Clapper, redOrbit) Synthetic Biology Explained (techNyouvids, YouTube) Transgenics: A New Breed of Crops (Daniel Cressey, Scientific American)
Do Bt Crops Affect Monarch Butterflies? (Canadian Food Inspection Agency) Regulation of Genetically Modified Food (Health Canada) Twenty questions on genetically modified foods (World Health Organization)
Hilleman, MR. 1987. Yeast recombinant hepatitis B vaccine. Infection. 15(1):3-7. Netherwood T, et al. 2004. Assessing the survival of transgenic plant DNA in the human gastrointestinal tract. Nature Biotechnology. 22:204-209.