Genetic Engineering of Foods - A Vegetarian Biologist Evaluates the Risks

The concept of genetic engineering tends to incite passionate responses. Either it's the passport to a brave new world where everyone has an abundance of perfect foods -- or an evil technology that will eventually destroy the planet. There seems to be little middle ground or dispassionate assessment of the potential and risks. As genetically engineered foods make their way to our dinner tables and vocal opposition to them gets stronger, the need for information has never been greater. As a molecular biologist and lifetime vegetarian, I have often been asked about this technology. Here, I will try to sort out the facts from the hype and give an impartial evaluation, with an emphasis on the genetic engineering of foods.


Genetic engineering has been around for over 20 years, but has steadily become more widespread and efficient. As with many technologies, public understanding has not kept pace with its practice. Overall, it's really quite simple. All living things have the information required for their growth and reproduction coded in their DNA. We now have the ability to read and make sense of this information. We also have the ability to take the DNA from one organism and put it in another organism. Except for some potential problems with specific transfer methods mentioned below, the details of how this done are not that important and subject to change as the technology changes.


The important thing to keep in mind is that all the characteristics that make different organisms different (plants and animals as well as bacteria) are encoded in the DNA. If you alter DNA, you change the essential character of an organism. This is powerful technology and is in fact the very nature of genetic engineering. All technology carries some risk (especially powerful technology) but the majority of us accept the risks from most technologies because they are small when compared to the benefits (or simply because we don't have much choice). However, as is often the case, proponents tend to minimize risks, and opponents tend to exaggerate them. To be fair, this technology hasn't been in use long enough to evaluate the risks with a track record of any length.


Proponents argue that genetic engineering is just an extension of traditional selective breeding. Opponents say it's so different that we may be courting ecological disaster if it's not stopped. On this point, I believe that both are wrong; genetic engineering is an extension of traditional selective breeding in the same way that a super computer is an extension of the hand-held calculator. In each case, they may broadly do the same thing. But genetic engineering, is a quantum leap beyond the traditional methods. Genetic engineering can be used to do things that are impossible to do any other way.


On the other hand, DNA does not always respect species boundaries as opponents claim. In fact, there are many documented cases of DNA, from even divergent species being exchanged. Novel arrangements of genetic material (DNA) are the raw material of evolution. We owe our existence (all plants and animals on the planet in fact) to a rare combination of two very different cells that genetic engineering opponents would say should never have been brought together - but did - some two billion years ago. Less drastic exchanges take place in nature more frequently, albeit sporadically and rarely. One such type of transfer occurs when a species picks up a gene from a parasite or the parasite from its host. Most transfers of this nature are never passed along to future generations, but some are. Nature has both vast amounts of time and incredible numbers of organisms to "experiment" on. This combination makes very rare events almost certain to happen, eventually.


For this reason, I believe that the risks to the environment are overstated by opponents. This is not to say that there is no risk, only that a false premise can lead to false conclusions. Even if you accept that genetic transfer isn't really new to nature, when humans have a hand in something the risks often increase. Interestingly, genetic engineering opponents claim that species boundaries are absolute in nature and this is why genetic engineering technology is so risky; but they also say that once transgenic organisms are released into the wild, the inserted genes will spread to other non-target species. These can't both be true! In fact, there is a risk that a gene or genes placed in one organism will spread to other species in the wild - specifically because these natural transfers do occur. This is cause for some concern, but is quite specific, as I explain below.


The natural transfer of DNA that has been genetically altered is only important if that gene confers some advantage to the recipient. Many of the genes we insert into plants (and animals) make changes that are of benefit to us, not to the engineered organism. The same can be said of traditional breeding methods, by the way. We select for traits that we want, not necessarily those that are good for the organism. Critics correctly point out that bacterial antibiotic resistance genes are sometimes transferred along with the target gene. These are pieces of DNA that we certainly don't want to be spreading about haphazardly. Again, if DNA stayed neatly in the transgenic organism there wouldn't be a problem, but it doesn't. On the other hand, the use of antibiotics by the livestock industry probably causes more harm than having one of these genes in corn plants ever will.


The arguments made about inserted genes disrupting normal cellular function by knocking out vital genes in the target cell are largely baseless. Yes, the insertion process is random, but any cells that had the new DNA knock out an important gene wouldn't survive. Furthermore, once new DNA has been integrated into it's new home, it's easy to determine its location -- and select only those cells where it has inserted in an appropriate location.


Some further points raised by critics regarding the effects of having a novel gene expressed in an organism are valid. Many transgenic organisms express the inserted gene(s) at high levels relative to natural genes; in many cases this is the point of inserting the gene. There certainly can be unintended side effects. Having a novel gene expressed, even at low levels, could potentially cause problems that can't be predicted. Some of them might be harmless, others may not be. Everyone agrees that allergic reactions are a big potential problem. Genes from highly antigenic organisms, like peanuts, inserted into other un-labeled food plants could even be deadly for some people.


In light of the above concerns, the policy of passing transgenic organisms for public consumption (as food crops or producers of drugs) without stringent testing is foolish. There are enough unanswered questions that testing and labeling should precede distribution. The animal rights "catch-22" is that this kind of testing would almost certainly involve animals.


Critics claim that genetic engineering is a threat to vegetarians and people who avoid foods based on specific religious dietary laws. As a vegetarian, I have a problem with animal suffering, but not with animal DNA or proteins. I have no objection to a plant that produces a protein also produced in an animal. This is a rather subjective argument, and while I can understand why many vegetarians do not want to eat plants containing animal proteins, I can also see that animal proteins produced in plants could conceivably reduce animal suffering. For example, genetically engineered insulin can replace slaughter house derived insulin and genetically-engineered plants could become excellent sources of vitamin B12.


As with most technology, it's the application of the technology - not the technology itself - that matters. Unfortunately, genetic engineering technology is used almost exclusively by large multi-nationals whose goals are, first and foremost, profits. They are promoting genetic engineering and doing their best to convince governments to forego labeling and testing. Our food supply has become dominated by these giants over the last few generations, and genetic engineering is only the most recent technology utilized. Recently, however, the genes to produce vitamin A have been inserted into rice to reduce the number of people who suffer vision impairment and blindness from a lack of this vitamin. This effort is not a money-making venture for multi-nationals but a sincere effort to change a staple food crop to benefit people.


In summary, genetic engineering of food crops holds potential to reduce animal suffering and perhaps feed more people but will certainly be used to enrich large corporations. There are valid concerns regarding safety that call for further testing and labeling, but concern for environmental devastation is probably overstated.