Tinkering With Nature: 1) GMOs

In my last blog piece, I mentioned rather flippantly and in passing that Hillary Clinton stands, by and large, in favour of the use of GMOs (genetically modified organisms). Trump’s views would seem to have been restricted to a hastily deleted tweet suggesting that Ben Carson’s lead in Iowa was due to Monsanto’s (GM) corn that “creates issues in the brain”. Fair to say, he might not be so in favour – in line with many Republicans. That is, I promise, the last reference to the presidential election for a while. But this concept goes well above and beyond elections and similar; it represents one of the most hotly debated “science and ethics” points in the current day.

The phase “genetically modified organism” doesn’t exactly conjure up friendly images to the unfamiliar. Indeed, you might be imagining something more like this:

alien
A genetically modified organism. Or, not.

(To be fair, this might have something to do with the fact that, if you’re googling for GMOs, then there are probably going to be more images of things looking “abnormal” than the majority that look very much the same as the non-modified version, most of these coming from anti-GMO campaigns and so on).

But what actually is a GMO? As the term implies, it refers to any organism that has had its genetic material – that is, its DNA – modified in some way, through the use of genetic engineering techniques. This typically means gene deletions (or, parts thereof), gene insertions, gene mutations. Bear in mind that, given many organisms have many thousands of genes, and the alterations may be extremely small within a gene, the changes, from a biochemical perspective are not large. So, chances are, you’re probably not going to end up with Mr. Mutant Alien above. Furthermore, whilst some gene additions may give rise to transgenic organisms – i.e. genetic material from a different organism is introduced – in many cases, it is genetic material from the same species that may be added.

To take some examples, and starting with one of the simplest and earliest, bacteria such as E. coli are routinely subjected to genetic modification in a laboratory context. Indeed, as i type this, I am genetically modifying some bacteria right now (I’m not a multitasking wizard, it’s not a particularly labour-intensive job…). In our lab and a huge number of other academic labs, we routinely use bacteria to generate particular proteins for our studies; to do this, we typically have to put the DNA that encodes that protein into the bacteria. It is genuinely one of the most standard techniques in molecular biology, far from being some sort of dark art in this context. Subsequently, the technology developed and was applied to more complex organisms such as mice and plants, and indeed, more recently, scientists at the J. Craig Venter institute synthesised an entire bacterial genome. Today, we have, for example, genetically modified corn, salmon, and the first genetically modified species to be sold as a pet, “Glofish” (below).

glofish
“Glofish”, the first GM pet

Evidently, as science has grown in this area and genetic modification in ever more complex organisms becomes increasingly routine, GM products have become more prevalent, and in turn, the debate concerning their use has raged ever stronger. There are indeed a range of arguments for and against the use of genetically modified organisms and products derived from them in everyday life. Here, I briefly discuss some of the key ones.

One of the most immediately relevant arguments for GMOs is undoubtedly the “feed the world” concept. Genetic modification gives us the power to, for example, create drought-resistant crops that will grow (faster), and even in harsh, arid conditions where alternatives are few, or to create more nutrient-rich foodstuffs. It would be ludicrous to suggest that this sort of approach will alone solve all the problems of potential famine etc associated with an ever-growing world population. Equally it seems slightly ignorant to suggest that it would not be beneficial in any way.

Furthermore, a well-documented advantage of some GM crops is the potential to make them pest- or insect-resistant, through simple introduction of a gene encoding this characteristic. Pesticides and insecticides are, really, none too pleasant. Nature probably isn’t such a huge fan of being sprayed with loads of chemicals. So if GM crops can lead to a reduction in the use of these items, this is, one would think, a good thing.

GMOs can even lead to better-tasting food (wave goodbye to that disappointment you get after the first bite into a below-par apple…or is that just me?); put in a gene for flavour enhancement, and hey presto. For example: https://www.scientificamerican.com/article/gm-tomato-tastes-better/. Much as I do very much enjoy food, I’m not going to rave about this point too much, because as far as I’m concerned, such “cosmetic” concerns rank about the lowest in importance. If I want good-tasting food, I leave the UK can probably find it anyway, and I believe the other benefits rather outrank this one. Still, nice to know.

In general, GMOs can provide better nutritional value, better growth characteristics with resistance to e.g. harsh climate, disease (for example, GM salmon that can flourish year-round), and can be more environmentally friendly, since fewer chemicals are required to help their growth, amongst a host of other advantages. This sounds pretty good really. So why would you not use them?

One frequently-cited argument is the concept that the use of GMOs, particularly with regards to crops, enables larger businesses to flourish at the expense of small businesses or independent farmers, since the latter lack access to the requisite technology. However, as I hope I outlined above, the technology itself is not overly complex – heck, even I can do it – nor does it actually require huge amounts of expensive equipment (to the best of my knowledge). Indeed, whilst the lack of access may be true, this may itself be a reflection of the strict regulations in place at present concerning GMOs. It’s kind of a vicious cycle.

Perhaps a greater concern is the effect of GMO species on the environment. What happens, say, if you take a GM fish and put it in the Atlantic? There is a fairly simple answer here at present – nothing, because it’s not happening. But hypothetically, one might envisage three basic scenarios: 1) Fish’s genetic modification gives it a competitive advantage over other fish, allowing it to gradually usurp the non-GM-fish population; 2) Fish’s genetic modification, whilst being highly beneficial for our own purposes, is actually detrimental to its own survival, giving it a selective disadvantage, and it fails to propagate; 3) nothing whatsoever, the genetic modification is effectively “neutral” in terms of selective advantage/disadvantage. There is no inherent reason to suppose that any one of these scenarios is more likely than the other; each situation has to be treated on a case-by-case basis at present, that it depends entirely on what sort of modification we are talking about. E.g. if we deliberately made a larger variant of a fish so as to gain more consumable per species, sure it might be stronger than natural fish, but it might also be somewhat slower (and remember, differences are small – we’re not talking about transforming a salmon into a shark). But just to emphasise: at present, such species are so tightly regulated that none of the above scenarios could play out, yet.

With regards to crops, the situation is perhaps a bit clearer, because the modifications we’re talking about here are very frequently aimed precisely at the improvement of survival and propagation characteristics; what is good for the plant is in most cases good for us as consumers too. Crops are slightly harder to contain owing to e.g. wind-carried pollen and so on, but with appropriate knowledge and understanding containment this can at the very least be minimised. Furthermore, in relation to both this and the preceding paragraph, in numerous instances GMOs would surely fact be beneficial to the environment, such in cases where a necessary nutrient currently derived from endangered species could be replaced by the same nutrient from a readily available GMO.

It’s been a while since any pictures, so here’s a random one of some GM crops:

Research field
GM crops

A frankly rather amusing yet apparently genuine complaint against the consuming of GMO-derived products (corn, fish, whatever) is the idea that the genetically modified DNA that we thus digest might somehow find its way into our cells, combine with our own DNA, and cause general havoc. If this did actually happen, havoc most likely would ensue. But if you stop and think a minute, this is a bit illogical. Ingested DNA is digested down to constituent parts that are small enough that they are common to essentially all organisms; no matter what species you are, your DNA is made from the same (4) molecules, but it is their precise sequence that differs. But it would be very rare for a DNA sequence of sufficient length to be discernibly “non-human” or “different” to survive through digestion, let alone to enter our cells and combine with our DNA. There is, to be fair, a paper claiming that such large DNA fragments could in fact survive (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0069805), but subsequent reviews suggest this DNA in fact results from contamination. Seriously, though, I eat a lot of meat, and I’ve yet to turn into a chicken, sheep, cow, or whatever. I don’t think I will, to be honest. And I fail to see how this particular anti-GMO stance is hugely different. There’s a cracking article on this here: http://www.skepticalraptor.com/skepticalraptorblog.php/gmo-foods-transfer-dna-humans-another-myth/

flickr_big_bird
Eat too much chicken and maybe you’ll turn into this!

 

Indeed, many of the anti-GMO concerns have a common factor: the “what if?” question. Many of them are based on hypothetical events of the future. GMO salmon have not taken over all fish species. I don’t believe anyone has, or has had, cancer that can be directly and unambiguously attributed to GMOs. The “large business domination” point is perhaps more based on current fact, but I’ve already discussed how this largely reflects the restrictions on GMOs at present, which are themselves a consequence of…the other concerns. I will, however, acknowledge the potential adverse affect GMOs may have on allergy sufferers, without going into it in any detail (essentially, introducing new genetic material might introduce an allergy); this is certainly a valid concern, but one that is manageable with proper testing of the products in question.

So really, the main concern is quite simple, and totally understandable: a lack of knowledge. As one would expect, science has advanced further and faster in the area of genetic modification techniques than in understanding the potential consequences of them in practice. The advent of CRISPR-Cas9 DNA editing (see next post) renders genetic modification in increasingly complex systems ever easier. We cannot in any good faith predict what the effect of GM crops, GM fish, GM anything else, will be on the environment, on ourselves, on businesses. But equally, there is, to my knowledge, a lack of strong evidence in practice as yet for their harmful effects (if you do know of significant quantities of such evidence, I’d genuinely be very interested to hear). In the case of a new drug, the same scenario unfolds: one cannot predict how it will affect humans, what side effects it might have, no matter how many “model studies you do”. But then, it goes through the clinical trial process. You could do the same for GMOs effect on people (but this would get pretty laborious), but how do you run a “clinical trial” where one of your subjects to be tested includes the non-generalisable entire earth environment? Well actually, it’s running now. And we are all the guinea pigs. As with so many things in the past (tobacco, anyone?), we learn from experience, be it positive or negative.

In a sense, it is a question of outlook. Are you an “innocent until proven guilty” person, or a “guilty until proven innocent” one? (Personally, I’m more of the former, in case you hadn’t guessed). Some GM technology, in particular that used for crops, in which case a selective advantage (better growth, better survival etc.) is almost always the aim, is essentially “accelerated evolution”. Through natural selection, changes that confer a selective advantage would happen anyway, just rather slower and more randomly than with the precision of GM. Indeed, many kinds of genetic modification – insertions, deletions, mutations, even cross-species transfer – could, and do, happen naturally. Even if they conferred a selective disadvantage, they could still happen, they just wouldn’t survive.

In my next few blog posts, I’ll look in more detail at some of the recent techniques developed for “tinkering with nature”, or in particular, for editing three fundamental biological macromolecules. GMOs concerns the editing of DNA, and I’ll look at this more closely, in particular at the relatively new and often-flaunted CRISPR-Cas9 technology, in my next article. Following this, I’ll delve into my own field of research – modification of proteins – before wrapping up this mini-series with a discussion on some of the ways in which scientists alter carbohydrates in vivo. Stay tuned.

 

 

 

 

 

 

 

 

 

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