Many of us have strong reactions to the word GMO and I would wager that many of those people do not understand why they feel so strongly about them or, even more fundamentally, what a GMO even is.
I felt that I understood what a GMO was and because I thought I knew what they were, I believed I had a choice to avoid them. However, my husband and I were recently at the Home Depot and I decided to get some last minute broccoli seeds. My husband was immediately drawn to these bright green packages that clearly stated non-GMO. I wandered away from those packages because it was not clear whether they were Hybrids and they were not organic. When I went to the other side of the seed display and saw the organic offerings of a large seed company, I noticed that there were no non-GMO claims on the label. Nonetheless, I felt confident that home garden seeds had not been breached by genetic modification and that my husband was confusing hybrids, or traditional plant breeding, with genetic modification. I insisted that I was not at risk of getting GMO seeds even if it did not say so on the label and I was pretty sure that organic meant that it was not GMO. But a tiny part of me wasn’t exactly sure. I was making a lot of assumptions and I hate not being right, so I thought I would explore. And it turns out that this is going to be a 2 or 3-parter… because the background part got really long. I hope you come back for more!
In order to delve into this question on the non-GMO-ness of garden vegetable seeds, let’s first take a step back and figure out what GMO means. GMO stands for gentically modified organism. You so totally knew that, I know. But just in case you wanted to read this to your seven year old, I am going ultra basic here. The scientific field in which this happens is called recombinant technology or biotechnology. Other terms are Genetic Engineering and BioEngineering. These are all terms that should make you perk up and pay attention. In general, in relation to plants, the genetically modified (GM) industry explains that biotechnology is the creation of plants with traits that you cannot develop from traditional plant breeding. The non-GM people tend to agree with that. They tend to believe that traditional or conventional plant breeding ascribes to the laws of nature.
But this is the part that I find confusing and the line that I do not think is entirely clear. It is also the part that I think weakens the non-GMO argument. The problem, you see, is that anti-GMOers keep wanting to argue that traditional plant breeding creates plants in a natural way or that plant-breeding is a gentle science, allowing plants to live their lives and just waiting to see what might happen. Certainly, it can work that way. This article I came across describes organic plant breeding and shows that this type of plant selection can be very gentle. It can also take years and years. It soon becomes clear why plant breeders might not have enough patience to just wait and see what happens. More than that, plant breeders want or need to create new plants. Historically, breeding might have happened the in the field where we might have been after plants that performed well under stressful conditions such as longer periods without rain, periods with too much rain, too hot, to cold, etc. These were conditions that would have occurred naturally and the plants that survived those conditions would be selected either intentionally or because it was the only thing growing. But breeders have not stopped at natural conditions to cause stress. They have subjected plants to gamma rays, x-rays, thermal neutrons (whatever those are), and radiation–all to induce mutations. For an eye-popping list, click here. There’s a lot of fruit on that list.
Beyond just mutating genes, breeders also develop new plants by crossing between existing plants. And, again, non-GMOers tend to argue that breeding creates plants that obey the laws of nature and that plant breeding is really just establishing an environment that encourages or speeds up natural crosses between varieties or species. But that is not accurate. Plant breeding is not necessarily gentle and plant breeders cross plants that would never naturally cross. Plant breeders, in fact, breed hybrids between plant genera as well as plant species. Because Biology class was probably a long, long time ago, this is how life breaks down:
Now, plant breeding can be gentle, such as the pollen of one variety of tomato getting brushed on the lady parts of another variety. These tomatoes are in the same species and this cross might happen naturally with bees busily buzzing around. But that is not what breeding is limited to. Breeders create new plants by crossing between species all the time. Think plums and apricots (pluots)-both species in the genus prunus. Scientists seem to support that this can happen naturally–or, at least that it is fairly easy to do. However, breeders don’t stop there. Crosses in the plant world between genera are referred to as wide crosses, and plant breeders do this with some regularity as well. After a relatively short search, I found several examples of wide crosses and even discovered an easy way to identify intergeneric crosses. (See this article.) The author of that article explains that “[f]or plants from different genera to successfully cross, they must share the same chromosome number and enough similarity in their DNA sequence to match up in enough places to create a viable seed. Intergeneric hybrids … are relatively rare in the plant kingdom as a whole. I know of no examples where they occurred without the helping hand of man.”
This article, which I will admit is so technical it made my eyes cross, demonstrates that crossing genera is not exactly natural. The wide cross made here required that embryos from the two plants were dissected and then plated on HLH medium–I’m not really sure what that is, but it certainly was something that helped recombine the embryos since without help that embryo would not have survived to form a seedling. This article explained that it can take a lot of effort to make an embryo viable. This type of crossing–really, any type of crossing–is, in some form, recombinant. In an enthusiastic defense of conventional plant breeding and its differences from genetic engineering (GE) this author argues that, “while wide crosses, as breeders perform them, do not occur in nature, they represent only a slight stretching of the boundaries of what can occur in nature. In a sense wide crosses represent a stretching of these boundaries by inches compared to miles with GE. After all, with GE, one can mix genes not only from widely different plant families, one can put genes from any organism on earth, or can create genes which have not existed before and put them, into plants.” This defense highlights the slipper slope of the debate. They are essentially saying that stretching the bounds of nature somewhat is okay, but not too much.
And this is where I think that the arguments start to weaken against GMOs. I don’t say this as a proponent of GMOs, but as a proponent of putting arguments out there that can’t be so easily refuted. Non-GMOers should stop saying that plant-breeding is okay because it is obeys the laws of nature. Most wide crosses would simply never, ever naturally exist, no matter how close together you put the plants you were trying to cross and no matter how long you waited for them to cross. The Non-Gmo project defines GMOs as “living organisms whose genetic material has been artificially manipulated in a laboratory through genetic engineering, or GE. This relatively new science creates unstable combinations of plant, animal, bacteria and viral genes that do not occur in nature or through traditional crossbreeding methods.” It is only the second part of this definition that separates GMOs from traditional plant breeding, since we have established that traditional plant breeding created organisms by manipulating their genes in a lab. It isn’t even the unstable, natural part in the second sentence that separates the two sciences, since traditional plant breeding creates unstable plants all the time that do not occur in nature. It really just comes down to the combination of plant, animal, bacteria, and viral genes that don’t occur in nature. That last clause leads me to to ask, “Well, what combinations of those genes do occur in nature?” An article published on June 20, 2013 in The Scientist Magazine claimed that a University of Maryland School of Medicine Study found strong evidence that bacteria transfer their genes into human genomes. Another article in The Scientist Magazine published much more recently states that horizontal gene transer “definitely can happen and has happened during evolution, and has played a role in shaping functional diversity of the gene repertoire in metazoans.” Accordingly, there is already, historically, some combination of bacteria and animal DNA that occurs in nature.
After all this research, I can honestly say that I am not a fan of GMOs, though my reasons are more solidly in the agricultural-ecological-economical camp. I am just not buying the whole science of it. The strongest argument I have come across is that we need more research because the way the DNA is introduced in GMO plants is unnatural and random and the consequences of re-sequencing of DNA in this way is unknown. This is the strongest argument because the results are, well, unknown… but they could be benign, they cold be harmful. But, one of my first thoughts when hearing this argument is that randomly inserting genetic material just sounds like another mutation, which is just a change in the DNA–often an unpredictable change. And mutations caused by stress, disease, and even radiation seem to be accepted as okay. It seems to me that, if an apple tree developed a mutation that led to a desirable fruit, we would likely graft that apple tree and sell it. But we probably wouldn’t question how the rearranging of DNA in that apple would affect our bodies. Research into how GMO plants affect our bodies should be done because we need to know how anything we eat affects out bodies. However, I don’t know that research will show that it is bad for you or changes anything in your body. Again, it is not necessarily a science argument that sways me from GMOs. It is the economic and agricultural devastation that they are wreaking and the poisons they require to grow. I plant to discuss that in the third part of this series.
In the next segment, I will actually get around to discussing whether vegetable seeds are GMO even if they are not labeled GMO. Your comments are more than welcome. However, I know that people get very heated about this topic, so please remain civil.
Click to access Introduction_to_On-farm_Organic_Plant_Breeding.pdf
When I think of a genetically modified organism in terms of plants, I think of a plant that has had genetic material from non-plants.
Are hybrids genetically modified? In a strict sense, yes.