The controversy surrounding genetically modified organisms (GMO) has intrigued me for some time, and recently I have been reading everything I can on the topic. It is an excellent topic for skeptics – it is mainstream (not a fringe topic), it has real importance for society, there are complex scientific and logical issues to sort through, and the topic is rife with misinformation and motivated reasoning.
I wrote recently about the fact that beliefs concerning GMO tend to be dominated by two opposing narratives: GMO critics despise corporate control and greed, and fear the unnatural, while GMO advocates see this technology as an example of the triumph of human ingenuity and science. I admit that with regard to this issue my bias is toward the latter narrative, however, I can understand caution regarding huge corporations (the tobacco industry comes to mind).
But, as a skeptic I have really tried to follow a critical thinking process and pull back from my initial gut reactions. Here, then, is my overview of the issues regarding GMO.
A Brief History of GMO
GMO advocates are quick to point out that pretty much all the food consumed by humans have already been extensively modified by human activity. Corn, for example, was cultivated from teosinte, which looks nothing like modern corn. In fact, it took some detective work to figure out that they are essentially the same species.
Cultivation is mostly about artificial selection – saving the best plants from one year’s crop to provide the seeds for the following year. Repeat that a few thousand times, and you have the development of agriculture and all the food you recognize today.
Cultivation can also involve cross-pollination, creating a hybrid species in an attempt to get the best traits from closely related species. Using a combination of cross-pollination and artificial selection, breeders have created countless varieties of common plants. The black or purple tomato, for example, of which there are about 50 varieties, is high in flavanoids, which give them their color. Orange carrots were developed by a fortuitous mutation resulting in high levels of beta-carotine. This turned carrots into an important staple crop as a source of vitamin A.
Breeders who are impatient to wait for a fortuitous mutation to occur developed what is called mutation breeding – exposing plants to chemicals or to radiation that increases the mutation rate. Between 1930 and 2007, 2540 mutagenic plant varietals have been released.
Genetic modification is the latest technique for changing organisms to suit our wants and needs. The technology involves various techniques for inserting one or more specific genes directly into a target organism. There are two basic types of GMO – transgenic and cisgenic. Cisgenic involves inserting genes from closely related species, ones that could potentially cross breed with the target species. Transgenic refers to inserting genes from distant species – even from different kingdoms of life, such as putting a gene from a bacterium into a plant.
There are four types of GM plants currently approved for use: herbicide tolerance, pesticide production, altered fatty acid composition (for canola oil), and virus resistance. Many other potential applications are in various stages of development.
GMO advocates are quick to point out that GM technology is nothing new, and that it is simply an extension of the various technologies we have used for thousands of years to alter organisms. This is overstating the case, however – transgenic GMO is not just a new technique, it also opens up new possibilities, like putting a gene from a bacterium into corn. But it is legitimate to put GMO in its proper historical context. It is not entirely new. Contamination of genes from other kingdoms even occurs in nature through horizontal gene transfer.
In any case, the “it’s not natural” argument is fallacious. Meanwhile, GMO should be looked upon as a powerful technology, and such technologies can have both powerfully good and powerfully bad consequences depending on how they are used.