GMOs, flatmates and lateral gene transfer.

Right about one year ago, I was sharing a flat with some Spanish guys in the deep heart of Grácia, an historical neighbourhood in Barcelona. To be honest, those guys fitted quite well into the definition of “friki” – Spanish transliteration of the term “freaky” – that indicate that kind of people attracted by oriental spirituality, organic food, ecological behaviours, flea market handmade clothes and hemp derivatives of all kinds. Boldly and briefly: hippies. Being an ecologist activist with radical autonomist positions (I am a bit hippie too), I tend to have a good relationship with this kind of people, at least till the moment when they understand that I am working in Science, in Biology, and most importantly in Plant Biology. The path from me explaining my work, and they asking about GMOs is very short, and my efforts to explain that I just study the evolution of plants without modifying them are normally useless. And right about one year ago, I had to spend a whole afternoon defending my work, and debunking a lot of misconceptions of them.

Even though I am not getting into the details of the discussion, I will focus on the reasoning that a girl exposed at a certain point. While talking about the health risks, this girl (whose name lays somewhere in my burned memory) confessed that she feared a possible DNA transfer from the food to her body. More specifically, she was afraid that “synthetic” DNA could be absorbed by her body and modify her genome, with possible terrible consequences for her health. Although she had a biological knowledge limited to a high school level, I was hit by her statement, that perfectly resumed the two biggest biases that public opinion has when approaching GMOs- related issues, and it is not even that wrong under a biological point of view.

The “synthetic” DNA.

The first part is the fear of “synthetic” DNA. When biotechnologists affirm that they have modified a gene, inserted a new one, or even synthesized a DNA sequence, they tend to forget that the most of the people will understand that something “new, external and artificial” has been inserted in the organism. Under the typical oppositive dualism between “natural” and “artificial”, the most common expectation will be that an “artifical” gene it’s different from a natural one even under a chemical point of view. This “trans-DNA” will be taken as a “different material”, or better a “different compound” than the “natural” DNA, something “plastic” and “artificial” that is possibly able to trigger a different response of the organism as it is ingested. The fact that a “synthetic” DNA sequence is just a DNA having a novel sequence, that the most of the transgenes are genes found in related species, and that there is no difference between human modified sequences and the native ones as they are digested, is all but clear to the most of the people. The point is that we tend to take some concept for granted, whilst a better explanation could help in a better understanding between researchers and public opinion.

The DNA transfer from our food.

I can not deny that when I have heard my flatmate arguing that her food could transfer some DNA to her cells and “modify her genes”, I smiled a bit. My swift and ironic answer was honestly quite brash. I asked her to prove that she could turn green and photosynthesize after having eaten a salad, since the genes coding for the photosynthesis machinery could have “transferred to her body” at a certain point. This answer succeeded in making the point swiftly, but a deepening of the biological dynamics of what happens during digestion could take us into a completely different conclusion: does the DNA in food transfer to our organism as we eat it? The answer is actually yes.

The gene transfer between food and organism is limited, but very well described, and the first papers talking about this date back to some decades ago. The pivot role in this game is of course taken by the gut microbiota. The lateral gene transfer is a common way to exchange genetic material in bacteria, who can accept exogenous DNA from the food and eventually transfer it to the gut epithelial cells, as described in this great post on The Scientist by Kelly Robinson. There is no doubt about that the gene transfer is sporadic, limited and all but systemic as that girl could imagine. There is also no reason to affirm that GMO food has more probability to transfer DNA, or even the same transgene to our cells than normal food, but some huge misunderstanding could come up.

Just imagine a journalist (or worse, a blogger) who, after a swift search on Scholar, understands that food can transfer DNA to the intestine cells, and decides to thread this into the GMOs issue. Not to mention the possible awful implications of all this. Simple ideas diffuse faster that elaborated arguments, and alarmist news go viral very easily.


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