Recently, food columnist Ari Levaux wrote what can only be described as a completely unscientific article in The Atlantic claiming that microRNAs (miRNAs) are a "very real danger of GMOs." I won't go point by point through the horrendous inaccuracies in his piece, as Emily Willingham has more than hacked them to bits. But I do want to make a short comment on this idea that miRNAs are dangerous, and thus something we should worry about when it comes to what we eat.
Every plant and animal out there produces miRNAs. We, for example, are thought to produce thousands. These teeny-tiny snippets of RNA serve regulatory roles in our cells, attaching to bits of messenger RNA and causing changes in expression of different proteins. They are far from evil: indeed, miRNAs are necessary for cells to function properly.
Can miRNAs we eat alter our gene expression? Well, yes. That was the incredible scientific discovery made by the Chinese research team that was recently published in Cell Research. But to make the leap from 'miRNAs we eat can alter gene expression' to 'GMOs are dangerous' requires unbelievable gaps in understanding about GMOs and miRNAs.
First off, there's no reason to think that the DNA being introduced into GMOs is going to produce more/different miRNAs than it did in the original organism. Ari's claim that "new DNA can have dangerous implications far beyond the products it codes for" simply isn't true because miRNAs are coded for. These small RNA fragments aren't random or accidental - they are explicitly detailed within the genome. So a stretch of DNA that didn't code any miRNAs before isn't going to suddenly code for a ton of them when it's placed in a different genome. If we're worried about potential miRNA effects, we can screen genes we are considering transferring and determine if there is any chance they produce miRNAs before we shuffle around which organism they are in. Indeed, GMOs are tested genetically, to ensure that the target gene has incorporated properly and that the organism is producing the desired protein, and not unexpected products. Genetic modification is a very precise process, and there is no reason to think it would cause a sudden burst of miRNAs.
But perhaps more fundamentally, miRNAs are found in all kinds of life, including every single species that we currently eat. There's no logical reason that a new miRNA being produced by a GM plant is going to be more dangerous than the multitude of miRNAs we ingest when we eat the non-GM version.
In fact, the potential side effects of non-GM food is, very explicitly, what the Chinese research team showed: that of the millions of miRNAs we eat every day, at least a few make it from our stomachs into our blood, and that a specific one from ordinary rice can change the expression of genes in mice. So if miRNAs are dangerous - guess what? - you're already ingesting them every time you eat. And, to get a little gross, let's be clear: when we eat something, we don't just ingest the miRNAs from the species we intentionally eat. Did you know, for example, that foods you eat are allowed to contain mold, hair, insect parts, and even rat poop? All of those bits of organisms which we inadvertently eat have DNA, and - you guessed it! - miRNAs, too. If miRNAs are so dangerous, we would never have been able to eat anything previously alive in the first place.
But we can eat other organisms, and we will continue to, because, simply put, miRNAs aren't that dangerous.
Perhaps what ticks me off most, though, is that Ari's scaremongering overshadows the very real and interesting implications of the science he failed to cover. The notion that miRNAs may drive some of the interaction between us and our food is incredibly new and totally cool. As the authors write, their research suggests that "miRNAs may represent a novel class of universal modulators that play an important role in mediating animal-plant interactions at the molecular level. Like vitamins, minerals and other essential nutrients derived from food sources, plant miRNAs may serve as a novel functional component of food and make a critical contribution to maintaining and shaping animal body structure and function."
What if some of the benefits of drinking wine aren't from the antioxidants, but from the miRNAs present in grapes? What if we can produce beneficial miRNAs, and take them like we do vitamins? Or reduce the expression of harmful ones? Suddenly, we have been given a sneak peek at a whole new facet of nutrition science that we didn't even know existed. The amazing implications of this research - not some ludicrous and tenuous connection to anti-GMO propaganda - should have been what The Atlantic highlighted. Instead, they made a fool of themselves by allowing Ari Levaux to expose just how poorly he understands genetics.