GMOs are making news nearly every day and issues surrounding their safety are a source of ongoing bioethics debates in the food and biotechnology industry. What does the term GMO stand for and why is it such a controversial issue?
GMO stands for genetically modified organism. The acronym can apply to plants, animals or microorganisms, whereas the term genetically engineered microorganism (GEM) refers only to bacteria, fungi, yeast or other microorganisms. In both cases, however, these terms refer to a living organism that has been genetically altered using molecular genetics techniques such as gene cloning and protein engineering.
Recombinant GMOs can be produced by gene cloning methods in which a non-native gene is introduced and expressed in a new organism. Generally the new protein has also been somewhat modified, or engineered, for proper expression in the new host. In particular, differences between microorganisms and eukaryotic cells must be overcome, such as the presence or absence of introns, occurance of DNA methylation and certain post-translational modifications to the protein itself for proper transport within or between cells. The advent of PCR and gene sequencing methods have opened up the door to all sorts of manipulative techniques for changing the structure of proteins through genetic alterations.
The introduction of bacterial genes into cash crops, to enhance their growth, nutritional value or resistance to pests, is becoming rather commonplace in plant technology. One example that has made frequent headlines is the introduction of bacterial genes for natural pesticides into plants, in order to eliminate the need for chemical pesticide use. The drawback to this technology is public concern over the consequences of injesting these natural pesticides. Problems such as these might be alleviated by site-specific expression of the gene, or control of expression throughout the lifecycle. For example, it might cause less concern if expression of a pesticide gene in the leaves of young plants could be used to prevent foliage from being destroyed early on, without expression in the fruit later in the lifespan.
In the early 1990's, it was proposed that newly emerging genetic techniques could result in GEMs, or "superbugs", for bioremediation, that could withstand extreme conditions and rapidly break down the recalcitrant chemicals plaguing our waste sites and brownfields. Issues such as how to control the spread of these superbugs and prevent an ecological upset, have hindered their development. Numerous proposals have been put forth and tested, from programmed cell death mechanisms to bioindicators to track their spread. However, the bioremediation industry today has not been able to fully take advantage of the technology available for developing microorganisms that can quickly eliminate some of our most toxic environmental contaminants.
Despite efforts to control gene expression there are many unanswered questions and issues that arise and stand in the way of full acceptance of GMOs by the public. Fear of the unknown is one cause of public reluctance to use GMOs and GEMs. However, this concern is validated whenever a specific case proves the technology has gone awry, and is widely publicized. Examples of this are products that have allegedly caused the mass destruction of non-target insect populations by genetically modified cash crops or bioethical issues surrounding questions of seed ownership once a crop has been harvested, and issues over the cost of seeds and availability to farmers.
Arguments against the use of GMOs include industrialization of agriculture, pushing out the small farmers in favor of mass production of crops and due to legalities surrounding IP and ownership of seeds. Another argument is that exports of less developed countries will suffer while over-developed states take over. An example of this is use of biotech sweeteners instead of sugarcane products from the Third World. In addition to these arguments there are countless claims of toxicity and carcinogenicity of biotech foods, which may or may not be warranted, depending on the individual products.
Those opposed to the use of GMOs are also opposed to mass production of pharmaceuticals using cloned genes in plants, or fermentation products of yeast, bacteria or fungi. The benefits, however, to using this technology, might include reduced drug costs and greater availability, assuming, of course, that the technology is properly shared and applied and used for the good of everyone.
Cloning of animals has proven to be a complicated and risky endeavor. Cloned pigs, sheep or other animals experience a long list of illnesses and complications that usually result in premature death. Strong opposition to all GMOs, however, cannot be based on these facts alone. The insertion of a single foreign gene to make a transgenic plant, for the production of a drug that will be harvested and purified, is far less risky than cloning an entire pig with a human heart in order to harvest that heart for a human transplant patient. Likewise, cloned pesticide genes in food crops might be considered more risky, as they could affect the local insect population and upset the balance of nature, or adversely affect individuals who eat that food. Advocates for mandatory labelling of foods containing, or produced using GMOs, cite risks from unknown toxins or allergens that might be introduced during production, as their reason for caution.
For each of the above examples of GMOs and issues surrounding them, there are countless others. Each of the different examples of GMOs has a relevant and useful application in the biotechnology industry. Each situation is unique and presents a new series of issues to be considered when debating the benefits versus safety and risks involved with that product.