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    GMOs: Gene Transfer Is Neither Unnatural Nor Dangerous
    By Michael Eisen | June 19th 2012 05:00 AM | 13 comments | Print | E-mail | Track Comments
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    Prof. Michael Eisen is an evolutionary biologist at U.C. Berkeley and an Investigator of the Howard Hughes Medical Institute. His research focuses...

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    Last week I wrote about the anti-science campaign being waged by opponents of the use of genetically modified organisms in agriculture. In that post, I promised to address a series of questions/fears about GMOs that seem to underly peoples’ objections to the technology. I’m not going to try to make this a comprehensive reference site about GMOs and the literature on their use and safety (I’m compiling some good general resources here.)

    I want to say a few things about myself too. I am a molecular biologist with a background in infectious diseases, cancer genomics, developmental biology, classical genetics, evolution and ecology. I am not a plant biologist, but I understand the underlying technology and relevant areas of biology. I would put myself firmly in the “pro GMO” camp, but I have absolutely nothing material to gain from this position. My lab is supported by the Howard Hughes Medical Institute, the National Institutes of Health and the National Science Foundation. I am not currently, have never been in the past, and do not plan in the future, to receive any personal or laboratory support from any company that makes or otherwise has a vested interest in GMOs. My vested interest here is science, and what I write here, I write to defend it.

    So, without further ado:

    Question 1: Isn’t transferring genes from one species to another unnatural and intrinsically dangerous?

    The most striking thing about the GMO debate is the extent to which it contrasts “unnatural” GMOs against “natural” traditional agriculture, and the way that anti-GMO campaigners equate “natural” with “safe and good”.  I’ll deal with these in turn.

    The problem with the unnatural/natural contrast is not that it’s a mischaracterization of GMOs – they are unnatural in the strict sense of not occurring in Nature – rather that it is a frighteningly naïve view of traditional agriculture.

    Far from being natural, the transformation of wild plants and animals into the foods we eat today is – by far – the single most dramatic experiment in genetic engineering the human species has undertaken. Few of the species we eat today look anything like their wild counterparts, the result of thousands of years of largely willful selective breeding to optimize these organisms for agriculture and human consumption. And, in the past few years, as we have begun to characterize the genetic makeup of crops and farm animals, we are getting a clear picture of the extent to which traditional agricultural practices have transformed their DNA.

    Let’s take a few examples. This is a Mexican grass known as teosinte and its seed.

    Thousands of years of selection transformed this relatively nondescript plant into one of the mainstays of modern agriculture – corn. The picture below – which shows the seeds of teosinte on the left, and an ear of modern corn on the right – gives a pretty good sense of the scope of change involved in the domestication and improvement for agriculture of teosinte.

    Thanks to the pioneering work of geneticist John Doebley, and more recently an international consortium who have sequenced the genome of maize and characterized genetic variation in teosinte and maize, we now have a good picture of just what happened to the DNA of teosinte to accomplish the changes in the structure of the plant and its seed: a recent paper that characterized the DNA of 75 teosinte and maize lines identified hundreds of variants that appear to have been selected during the process of domestication. And maize is not weird in this regard – virtually all agriculturally important plants have a similar story of transformation from wild ancestors as generations of farmers adapted them to be easier to grow, safer to eat, more nutritious, resistant to pests and other stresses, and tastier.

    For most of history this crop domestication and improvement has been a largely blind process, with breeders selecting crossing individuals with desired traits and selecting the offspring who have inherited them until they breed true – unaware of the molecular changes underlying these traits and other changes to the plants that may have accompanied them.

    Modern genetics has fundamentally altered this reality. It has increased the power breeders have to select for desirable traits using traditional methods, and makes it far easier ensure that undesirable have not come along for the ride. And it also gives us the ability to engineer these changes directly by transferring just the DNA that confers a trait from one individual in a species to another. There are many ways to accomplish this – the most common involves extracting the DNA you want to transfer from the donor, placing it into a bacterium whose natural life-cycle involves inserting its DNA into that of its host, and then infecting the target individual with this bacterium. But recently developed technologies make it possible to effectively edit the genome in a computer and then make the desired changes in the living organism.

    When applied to transfer genetic information from one individual in a species to another, this is an intrinsically conservative form of  crop improvement around since is all but eliminates the random genetic events that accompany even the most controlled breeding experiment.

    The only difference between this and the generation of GMOs is that the transfered DNA comes not from a member of the same species, but from somewhere else on the tree of life. I understand why some people see this is a big difference, but modern molecular biology has shown us that all living things share a remarkably similar molecular toolkit, with the distinct properties of each species coming more from how these pieces are wired together than which ones are where.

    Transferring a gene from a fish into a plant does not make the plant swim any more than stealing the radio from someone’s Maserati and putting it into my Honda Civic would turn it into a high-performance sports car. Indeed, scientists routinely use genes from mice, fungi, plants and even bacteria to substitute for their human counterparts, and vice-versa – which they often do perfectly.

    And this doesn’t just happen in the lab. There are countless examples of genes moving naturally between species. Microorganisms swap DNA all the time – this is how antibiotic resistance spreads so quickly between species. Our own genome contains genes that got their start in bacteria and were subsequently taken up by one of our ancestors.

    The relatively low rate of such “horizontal gene transfer” in multicellular organisms like plants and animals compared to bacteria is more a reflection of reproductive barriers and the defenses they have evolved to prevent viruses from hitchhiking in their DNA, than from a fundamental molecular incompatibility between species.

    This is why I do not find the process of making GMOs unnatural or dangerous – certainly no more so than traditional breeding. And why I find the obsession with, and fearmongering about, GMOs to be so bizarre and irrational.

    Of course the fact that making GMOs is not inherently dangerous does not mean that every GMO is automatically safe. I can think of dozens of ways that inserting a single gene into, say, soybeans could make them lethal to eat. But it would be because of what was inserted into them, not how it was done.

    For what its worth, it would also be relatively easy to make crops plant dangerous to eat by strictly non-GM techniques. Essentially all plants make molecules that help them fight off insects and other pests. In the foods we eat regularly, these molecules are present at sufficiently low levels that they no longer constitute a threat to humans eating them. But it is likely that the production of these molecules could be ramped up when crossing crop varieties with wild stocks, or by introducing new mutations, and selecting for toxicity, much as one would do for any other trait. Indeed, there have been reports of potatoes that produce toxic levels of solanines and celery that produce unhealthy amounts of psoralens, both chemicals present at low levels in the crops. Which segways nicely into the next topic.

    NEXT: Question 2: Maybe GMOs aren’t automatically bad, but isn’t it obvious that it’s dangerous to consume crops that produce their own pesticides and can tolerate high doses of herbicides?

    Originally published on MichaelEisen.org June 9, 2012


    Molto interessante.  Ma SEGUE, non segway, per favore.  Si tratta di un termine musicale, il che significa 

              proseguire alla sezione successiva senza pausa.

    Tuttavia, una parola più appropriata in questo contesto.
    WTF? I just read one of the scientific papers you cited as evidence of safety of GMO's and first of all it isn't even a study demonstrating the safety of GMO's it was a discussion of methods of assessing and detecting the risks of GMO's, but the way you listed it on it's site("Safety of Genetically Engineered foods") makes it seem like a report on the safety of GMOs, this is dishonest, and the report itself even admits to the possibility of adverse health effects of GMos "Moreover, application of any technique to produce altered levels of or novel food components can result in unintended compositional changes that may in turn result in an adverse health effect.". how is this evidence of the safety of GMO's this was the only report on you site that I saw which addressed the safety of GMO's and it didn't even support the safety of GMO's, if you are going to claim that science is in support of the safety of GMO's then please cite the evidence demonstrating, this and not a report with a title that makes it sound like it's demonstrating the safety of GMO's and in actuality has nothing to do with the matter.

    You claim that advocates for GMO Labeling are anti-science, yet how do you explain this report by GE scientists, which cites independent peer reviewed literature which supports the possibility of harmful effects of GMOs? is this not a blatant lie? how can you say there is no science against GMO's when there clearly is? you claim to be unbiased yet you continually show a bias in your writing, when you only cite evidence for one side (which isn't even there), and ignore evidence from the other, and portray the other side as something their not.

    http://earthopensource.org/index.php/reports/58, here is the report I was refering to, again, sorry I forgot to link to it in my comment.

    crap I forgot to link to the report I was trying to cite, haha sorry I'm new to this, please forgive me, I'm still young I got time to learn. could someone please show me how to cite a webadress so theres a embedded link in my comment please?

    "how to cite a webadress so theres a embedded link in my comment please"

    Tonio, just don't put the web address in quotes and it will automatically appear as a link after you have posted the comment.

    BTW you made some good points but it doesn't look as though Eisen bothers to reply to comments, just one way traffic.

    Gerhard Adam
    Here's an article worth looking at:
    Mundus vult decipi
    This brings to mind the following, from Science Codex:

    Parasitic plants 'steal' genes from their hosts

    that the Malaysian parasitic plant Rafflesia cantleyi, with its 50cm diameter flowers, has 'stolen' genes from its host Tetrastigma rafflesiae. Analysis of these genes shows that their functions range from ... , especially parasitic plants and their hosts due to their intimate physical connections. Rafflesia ...

    for what its worth, it would also be relatively easy to make crop plants dangerous to eat by strictly non-GM techniques.
    “I say, the Seven Dwarfs think there is something very odd about that recent grant application from the Orchard Research Institute ...”

    Robert H. Olley / Quondam Physics Department / University of Reading / England
    Bonny Bonobo alias Brat
    Dr Eisen, I would be very interested to know your opinion regarding this recently published (June 2012) very comprehensive academic online document at the earth open source website called 'GMO MYTHS AND TRUTHS' which was mentioned in the comments section of your previous blog. It is an 'An evidence-based examination of the claims made for the safety and efficacy of genetically modified crops' that was written by Dr Michael Antoniou, Claire Robinson and Dr John Fagan :-
    Michael Antoniou, PhD is reader in molecular genetics and head, Gene Expression and Therapy Group, King’s College London School of Medicine, London, UK. He has 28 years’ experience in the use of genetic engineering technology investigating gene organisation and control, with over 40 peer reviewed publications of original work, and holds inventor status on a number of gene expression biotechnology patents. Dr Antoniou has a large network of collaborators in industry and academia who are making use of his discoveries in gene control mechanisms for the production of research, diagnostic and therapeutic products and safe and efficacious human somatic gene therapy for inherited and acquired genetic disorders.
    Claire Robinson, MPhil, is research director at Earth Open Source. She has a background in investigative reporting and the communication of topics relating to public health, science and policy, and the environment. She is an editor at GMWatch (www.gmwatch.org), a public information service on issues relating to genetic modification, and was formerly managing editor at SpinProfiles (now Powerbase.org).
    John Fagan, PhD is a leading authority on sustainability in the food system, biosafety, and GMO testing. He is founder and chief scientific officer of Global ID Group, through which he has pioneered the development of innovative tools to verify and advance food purity, safety and sustainability. He co-founded Earth Open Source, which uses open source collaboration to advance sustainable food production. Earlier, he conducted cancer research at the US National Institutes of Health. He holds a PhD in biochemistry and molecular and cell biology from Cornell University.
    There is a section 5.12 which addresses the myth that horizontal gene transfer from GM crops is unlikely or of no consequence and claims that the real truth is that GM genes can escape into the environment by horizontal gene transfer with potentially serious consequences. They claim that the basic mechanisms by which HGT could occur are :-
    ● Uptake of GM DNA by bacteria
    ● Uptake of DNA from the digestive tract into the tissues of the organism
    ● Transmission of GM DNA via Agrobacterium tumefaciens, a bacterium that is often used to introduce GM genes into plants because of its natural ability to carry and transfer foreign DNA and to infect plants through wounds in their outer layer
    ● Gene transfer by viruses 
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    wow, so this entire article is just industry disinfo BS eh?

    Yes, those liberal biologists at Berkeley are well-known for being right wing shills for Big Ag.

    Or, more likely, you simply do not like that the science disputes with what you want to believe.
    Gerhard Adam
    Decidedly in this case, without responses to legitimate questions, I'm afraid it's the GMO stance that is being unscientific.  Many of the arguments or cautions against, are not shrill alarmists, and deserve answers, especially when the author's own links don't paint a particularly positive picture.

    The explanations given here are fundamental, and simply avoid the real questions.  I'm not satisfied that because we've modified genes for centuries in ignorance, that somehow that translates into a ringing endorsement for doing it in the lab.  In addition, it seems that the focus is far too narrowly spent on specific safety of consumption.  It fails to address many of the other concerns expressed regarding pesticides and herbicides, especially given the recent history of usage, there should be reams of data available to demonstrate these changes/differences.

    I'm also disappointed that in using maize, the author failed to acknowledge the problems created by artificial selection, especially in the realm of animals where many traits that we selected for produced all manner of secondary problems in the animals [i.e. promoting blindness, hip displasia, etc. etc.].  Therefore, it is quite reasonable to question whether there are any potential downstream ramifications of such modifications, especially given the strikingly different way in which GMO's are produced.  In particular, I mean, that despite claims to the contrary, the reality is that the traits employed by GMO's could NEVER have been produced by artificial selection.  So, to claim that this is the same thing, is wrong.

    I also agree that there are far too many articles that thrive on innuendo and fear-mongering.  However, if this is going to be a scientific discussion, then I would expect to see some of the issues addressed with real scientific papers, and also see the results of open discussions around these problems.  Anyone that doesn't think these problems are real is lying.  The only way to understand GMO's is to see an honest assessment of the problems and what research has indicated the real risks or exposures are.  Those are the links that people want to see.f

    I'm quite positive that I'm not the first [nor are other commenters] to point out these difficulties, so I also know that there are many scientists that have examined these issues and undoubtedly published results.  If they are not available or hidden behind pay-walls, then shame on scientists, because in this kind of PR climate, that is decidedly naive.  If they are available, then that would be the best tool to let people read how those problems were addressed, so that we can all be more confident that GMO's are a well thought-out scientific application of technology, rather than just a blind run for high profits.
    Mundus vult decipi
    haha you think I'm left wing that's great.

    Gerhard Adam
    BTW ... Another problem in this discussion is the appearance of patronizing reassurances such as those in the title of this piece:
    GMOs: Gene Transfer Is Neither Unnatural Nor Dangerous
    OK, let's be clear that regarding GMO's the gene transfer is NOT "natural" and it always has the potential to be dangerous.  If it were natural, then we wouldn't need GMO's.  The point here is that instead of recognizing that people are quite aware that this is something different and the result of newer biological technologies, AND, that it has the potential for danger, we are presented with this kind of "reassurance".

    Of course, it doesn't provide reassurance, because most people recognize it as being patronizing.  I would rather see a mature recognition that it isn't "natural" and potentially dangerous, but that these issues have been properly addressed and this is how they are proposing they be handled.

    Once we acknowledge that, then we can quibble about how "natural" or "unnatural" it is, etc. but then we'll at least be talking about something that we clearly understand is a human manipulation in biology and we also clearly understand what risks we are taking and the steps taken to mitigate them. 
    Mundus vult decipi