Debunking myths on genetics and DNA

Monday, October 29, 2012

GMOs love me, GMOs love me not..

I've been asked to discuss genetically modified foods and I confess I've been procrastinating. Why? Because I don't have an answer on whether or not GMOs are good or bad, and I can't offer one. But, what I can do is offer a few thoughts. Food for thought is usually super-natural, organic, and pesticide-free, so here it goes. :-)

1. What are GMOs?
Technically, all domesticated plants and animals are "genetically modified" since, rather than letting the species evolve through natural selection, mankind has steadily selected offsprings according to some man-made criteria. However, today's technology allows us to artificially modify an organism's genome. The difference between the two is not just in time scale: when selecting crops, or, more in general, any organism, generation after generation based on phenotype, uncharacterized genes are introduced in the species. Genetically engineering, or bioengineering, however, introduces a few well-characterized genes (often from a different species) into the organism. In a way, this is no news: gene therapy creates genetically modified organisms. Humanized mice are created in labs to test drugs and other therapies. The question of whether or not GMOs are good arises in the food industry. Are they safe to eat?

2. The Cartagena Protocol on Biosafety
As California gets ready to cast its vote on Proposition 37 [1] (which would require foods to denote their GMO content on the labels), it is good to review what currently is in act to "protect" us from possible hazards. From Wikipedia:
"The Cartagena Protocol on Biosafety is an international agreement on biosafety, as a supplement to the Convention on Biological Diversity. The Biosafety Protocol seeks to protect biological diversity from the potential risks posed by genetically modified organisms resulting from modern biotechnology."
"The Biosafety Protocol makes clear that products from new technologies must be based on the precautionary principle and allow developing nations to balance public health against economic benefits. It will for example let countries ban imports of a genetically modified organism if they feel there is not enough scientific evidence that the product is safe and requires exporters to label shipments containing genetically altered commodities such as corn or cotton."

3. Why are foods genetically modified?
For a number of reasons, some good and some not so good. Some are just practical reasons in a world that, whether we like it or not, is getting more and more "globalized": the first bioengineered produce was a tomato designed to have a prolonged shelf life. Some crops are genetically modified to resist harsher herbicides and pesticides. Others, are genetically modified to desist bugs from eating them. For example, genes producing Bt toxins have been introduced in cotton and corn. These toxins kill caterpillars that would otherwise eat up the whole crop. Notably, the modification benefits not only the genetically modified crops, but, since it reduces the global population of harmful caterpillars, it also benefits the non-modified crops.

I expect foods that can resist herbicides to be soaked in chemicals. On the other hand, if a crop is genetically modified so its flowers/fruits/seeds no longer offer a viable environment to certain parasites, I expect those foods to be pesticide-free. Yes, I'll take a few modified genes over harmful chemicals. Bottom line: NOTING WHETHER OR NOT A CERTAIN FOOD CONTAINS GMOs DOES NOT HELP. What you should really demand in a label is WHY SUCH FOOD WAS MODIFIED AND WHAT WAS ACHIEVED THROUGH THE BIOENGINEERING. Notice that while the Food and Drug administration currently does not impose any GMO labeling, their guideline recommendations state that the GMO content be noted, as well as the reason why the food was modified, and what was achieved through the modification.

4. Genetic homogeneity is bad
Rice is one of the most consumed crops in the world. Again, from Wikipedia:
"As of 2009 world food consumption of rice was 531,639 thousands metric tons of paddy equivalent (354,603 of milled equivalent), while the far largest consumers were China consuming 156,312 thousands metric tons of paddy equivalent (29.4% of the world consumption) and India consuming 123,508 thousands metric tons of paddy equivalent (23.3% of the world consumption). Between 1961 and 2002, per capita consumption of rice increased by 40%."
Rice is also highly "domesticated", as it has been selected over thousands of years to fit human needs. Currently, there are 20 different kinds of rice, but, according to FAO, the Food and Agriculture Organization, "It is estimated that not even 15 percent of the potential diversity has been utilized." This is a THREAT to food security. If a pesticide-resistant parasite were to attack rice crops, it'd be lethal to the vast majority of rice varieties currently harvested. Heavy use of pesticides favors the selection of pesticide-resistant organisms, while domestication favors genetic homogeneity in crops. This is NOT a good combination. Another reason why, between GMOs and pesticides, I'd favor GMOs. And if GMO research can prevent a pesticide-resistant organism to wipe out 50% of the world-wide food, hey, who's to complain?

5. Knowledge is NOT power if that knowledge is poorly understood
We live in a strange era when technology leaps forward at a higher speed than our ability to comprehend its output, especially in the field of genetics. We have loads of data we don't quite know how to store, let alone analyze. It's getting cheaper and cheaper to have a full human genome typed and companies are advocating that we do it for every individual. But are we capable of understanding the data? Last week I posted a shocking story of a boy discriminated because he carries a recessive mutation for a disease he doesn't have and he's at no risk of contracting (that's what recessive means). The Internet is full of bogus info on genes, genetics, mutations, etc. There's more noise than ever, giving people the illusion that they know when in fact they don't. I fear that the same will happen for GMOs. Once those labels come out, will people be able to understand what they mean? If Prop 37 will only require a "content" statement without a "reason", for example, will the information be really useful or will it just generate a stigma?

You now see why I cannot tell you whether GMOs are good or bad. They can be both! (Aren't we all?)

Food always has a higher impact than other things, but if you think about it, there are so many things that we've introduced in our daily lives in the past few decades that we simply don't know whether or not they are good IN THE LONG RUN: wi-fi, for example. Cell phones. Chemicals in skin products, from sun protection to cosmetics. I'm afraid the next generation will be the test. So the real question is: do we want to experiment with our children as guinea pigs? Sadly, when you put it in these terms, it seems to me it's too late to go back. The experiment has already begun.

If these few thoughts weren't depressing enough, read Pamela Ronald's review, referenced below [2]. One of the great points Ronald makes is that we are changing our climate and environment much faster than ever before (thanks to climate change and an exponentially growing population). Natural selection can't keep up with the pace, hence
"an important goal for genetic improvement of agricultural crops is to adapt our existing food crops to increasing temperatures, decreased water availability in some places and flooding in others, rising salinity, and changing pathogen and insect threats."
The review is clearly biased in favor of GMOs and it lists several benefits from such procedures. While advocating for adequate testing on every newly modified organisms, it also reports that all genetically modified crops tested so far have been deemed safe and substantially no different than conventionally selected crops "in terms of unintended consequences to human health and the environment."

Bottom line: I can't tell you what to vote on Prop 37 and I can't tell you whether or not you should avoid GMOs. Just read as much as you can and be sure to form your own opinion.


[1] Baker, M. (2012). Companies set to fight food-label plan Nature, 488 (7412), 443-443 DOI: 10.1038/488443a

[2] Ronald, P. (2011). Plant Genetics, Sustainable Agriculture and Global Food Security Genetics, 188 (1), 11-20 DOI: 10.1534/genetics.111.128553


  1. antisocialbutterflieOctober 29, 2012 at 7:17 PM

    I'm pretty much in the same place as you on this issue. I'd personally rather have a recombinant protein than a pesticide since the gastric system is built to break down proteins whereas the pesticide is more likely to make it to the intestine intact and be absorbed. This is a frequent argument with my hyper-organic father.

  2. EXACTLY!!! But isn't it mind-boggling how emotional people get when you talk about genes? Don't we eat genes all the time? Plus, what really had me thinking was the fact that when you selectively modify some crop you're still modifying genes but you don't know which ones! That review is a bit biased in the sense that to her GMOs are all good and no bad, and that I cannot believe (to be objective I think you need to present a bit of both), but still, it was quite fascinating that the one allergic outbreak it discusses came from the crop that was hand-selected, not the one that was bioengineered.

    Again, I'm not saying they're all good. But they shouldn't be demonized either.
    Thanks for your comment!

  3. I hate chems, but GMO's offer the same risks. Genes express together and separately. Changing even one without natural selection will change how other express as well. Also, those harmful caterpillars also have multiple purposes. Wiping them out en mas with GMO's would be the same result as killing them chemically. Also, if it kills "pests" -I hope science never decides we are one. So I see them all as equal-good and bad. (also a severe sufferer of proteins by nature scare the begebees outta me.-I know. I'm weird)

  4. Thanks for your comment, Katrina. I was having a similar discussion on G+ and noticed that people are a bit confused on the definition of "natural selection."
    In the population genetics literature natural selection is the selection of certain traits over others due to ENVIRONMENTAL PRESSURE. Man has been messing up with natural selection ever since the advent of domestication. Genes change all the time, even without natural selection because of genetic drift. Expecting genes not to change would be like expecting the ocean not to have waves. Yes, you may argue bioengineering is changing genes way faster than this would happen through domestication. However, we are already changing the environment way faster than any natural adaptation could possibly buffer. As the environment changes, genomes will become inadequate. And, finally, bioengineering controls exactly what genes are introduced. Domestication cannot do that.

  5. My thoughts pretty much mirror yours here. GMO's as with any technology can have positive or negative effects depending on their use and the method of their production (safety standards, etc).
    A label saying what the GMO is supposed to do would be really helpful as you say.
    Eventually, as gene therapy advances, we may all become GMO's.

  6. I hadn't thought about that, but you're absolutely right, Steve! :-)

  7. I really appreciated this article. There seems to be quite a bit of misinformation about GMO foods, and it was good to read a more balanced point of view.

    I like your idea of a label that explains the purpose for any genetic modification.

  8. Thanks so much, Jen, that's what I was going for, a (hopefully) balanced view.

  9. You're welcome! I have had many discussions with friends and acquaintances about "the harmful effects of GMO foods," yet so much of it is hearsay stuff. I personally don't like the idea myself, but have always thought there must be some benefits, even if it helps to increase crops so people can be fed!

    It does concern me that there does not seem to be enough information coming out to contradict some of the claims however.

    Anyhow, thank you again!

    1. Thanks so much, Jen, I REALLY appreciate it! :-)


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