Baseless fears of biotechnology
Debunking pseudo-science
Opposition to GM technology generally lack a scientific basis. The largest 'field trial' on earth comprises already more than 180 million hectares of arable land –corresponding to about 13 percent of all arable land on earth– dedicated worldwide to transgenic crops in 2011. No adverse effect on humans, animals or the environment have resulted from the growing or consuming of these crops. On the contrary, official reports from various countries show that pesticide use has been reduced almost 90 percent since the introduction of insect-resistant Bt cotton.
It would be most desirable if people who are sincerely concerned about the risks of transgenic crops expressed their fears in terms of concrete and solid arguments, in their own interest, because otherwise they might be missing on great opportunities for health and the environment without a valid reason. Factual argumentation can be dealt with, either by addressing the problem and making adjustments to the techniques used, or by providing solid data countering those arguments. Very often objections are based on assertions presented as scientific data, even though the underlying experiments have not passed rigorous scrutiny by peers, with pseudo-scientific reports following a circular line of argumentation. Sadly, these memes spread very quickly and become credo for a well-meaning but scantly informed audience, and the credibility is based purely on them being repeated over and over again.
This negative attitude has been condemned even by people who once were ardent fighters on that front, like Patrick Moore, one of the founders of Greenpeace. While Mr Moore and we still fight for the original ideal of a world where people and nature can live in harmony, some movements have forgotten their roots and end up entangled in futile politics and sensationalistic stunts, with fundraising and grooming of their own image becoming their sole reason of being. The negative impact of these actions has been well described by Mr Moore in an article published in the Denver Post entitled « Extreme Agendas Harmful»
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As an example of the controversy that has been created around Golden Rice we provide here a number of assertions posted by its opponents on the web under the title "Golden Rice is no technical improvement and more unsafe", followed by short replies to those objections. The assertions start with saying that Golden Rice exhibits all the undesirable, hazardous characteristics of existing GM plants, and in added measure on account of the increased complexity of the constructs and the sources of genetic material used. The alleged hazards are highlighted below.
- It is made with a combination of genes and genetic material from viruses and bacteria, associated with diseases in plants, and from other non-food species.
Our comment: The bacterial genome codes for anywhere between one and ten-thousand genes, only a few of them are involved in pathogenesis. The bacterial gene used in Golden Rice is clearly identified as a gene involved in the biosynthesis of carotenoids, and that is the only function it carries out in nature and in Golden Rice.
- The gene constructs are new, and have never existed in billions of years of evolution.
Our comment: This can be said about any gene that has developed throughout evolution. Also note that there have been multicellular organisms on Earth only during the last billion years and that not one single organism has remained unchanged over time. Would you prefer to remain a unicellular algae for ever?
- Unpredictable byproducts have been generated due to random gene insertion and functional interaction with host genes, which will differ from one plant to another.
Our comment: Only individually selected, well characterised transgenic events have been released. Plants derived from one single event all behave the same way in respect of the introduced gene or genes. In these events, the introduced gene constructs do not interrupt any genes in the neighbourhood.
- Over-expression of transgenes linked to viral promoters, such as that from cauliflower mosaic virus (CaMV), exacerbates unintended metabolic effects as well as instability (see below). There are at least two CaMV promoters in each transgenic plant of the 'Golden Rice', one of which is linked to the antibiotic resistance marker gene.
Our comment: The original versions of Golden Rice contained a CaMV promoter sequence (which has no other role than to direct a gene to be expressed), because during the proof-of-concept phase strong expression of the transgene was required. The new, released versions have only tissue-specific promoters that guarantee that the two transgenes are expressed only in the rice grain. Furthermore, the antibiotic resistance gene—, which by the way has been proved to be harmless and ubiquitous in nature— was introduced into a separate locus for the initial selection process, after which the gene was crossed out by conventional breeding. The final event contains only the two desired genes.
- The transgenic DNA is structurally unstable, leading to instability of the GM plants in subsequent generations, multiplying unintended, random effects. Structural instability of transgenic DNA increases the likelihood of horizontal gene transfer and recombination.
Our comment: Sounds almost like science, doesn't it? But the reality is that the transgene has been shown to be stable over many generations already, as have other genes expressed in commercilly grown transgenic crops around the world, having alreday reached over 180 million hectares in 2011, 40 percent of it in developing countries.
- Instability of transgenic DNA is enhanced by the CaMV promoter, which has a recombination hotspot, thereby further increasing the potential for horizontal gene transfer.
Our comment: As stated above, there is no CaMV promoter in released versions of Golden Rice.
- The CaMV promoter is promiscuous in function and works efficiently in all plants, in green algae, yeast and E. coli. The spread of genes linked to this promoter by ordinary cross-pollination or by horizontal gene transfer will have enormous impacts on health and biodiversity. In particular, the hygromycin resistance gene linked to it may be able to function in bacteria associated with infectious diseases.
Our comment: Most promoters in plants are functional across the whole kingdom. Nobody has yet come up with a scenario whereby the transfer of carotenoid biosynthetic genes, which are present in all plants, should have any effect on health or biodiversity. As to the antibiotic resistance gene, the hygromycin resistance gene is ubiquitous in nature and the antibiotic is practically not used in human treatment for that same reason (see also above). Moreover, viruses like the Cauliflower Mosaic Virus (CaMV) are widespread in nature, and their promoters do not get integrated routinely. Conversely, whole viral genomes can integrate into plants and become a natural part of them, like in the case of banana, where the whole genome of the Banana Bunchy Top Virus (BBTV) has long ago become part of the banana genome.
- Horizontal transfer of transgenic DNA from GM plants into soil fungi and bacteria has been demonstrated in laboratory experiments. Recent evidence suggests that it has also taken place in a field trial site for GM sugarbeets, in which transgenic DNA persisted in the soil for at least two years afterwards.
Our comment: Horizontal gene transfer are natural events that occur at an extremely low rate. There is no reason why the Golden Rice transgenes should be preferentially transferred over 30'000-plus other genes in the genome, and furthermore, if that happened at all, the genes would only be able to participate in the biosyntesis of carotenoids, which all green plants do anyway. The DNA of transgenes is no more or less stable than any other DNA, there is not one single reason why it should remain intact in the soil while the rest of the genome, which is made of exactly the same biochemical units, degrades in the soil.
- Prof Hans-Heinrich Kaatz from the University of Jena, has presented new evidence of horizontal gene transfer within the gut of bee larvae. Pollen from GM rapeseed tolerant to the herbicide glufosinate were fed to immature bee larvae. When the microorganisms were isolated from the gut of the larvae and examined for the presence of the gene conferring glufosinate resistance, it was found in some of the bacteria as well yeast cells.
Our comment: This study was widely publicised by opponents of GM technology, even against advice by the Prof Kaatz himself, given that it was only a preliminary finding, which more than ten years later has never been proofed to anybody's satisfaction, except for those who wanted it to be like that. The gene in question is that of a commonly found soil bacterium, and is routinely found in various insects. It would have been quite simple to prove the plant over a bacterial origin, because the DNA sequence surrounding the gene construct used in plants is known, but that experiment was never done.
- All cells, including those of human beings, are now known to take up genetic material. While natural (unmanipulated) genetic material is simply broken down to supply energy, invasive pieces of genetic material may jump into the genome to mutate genes. Some insertions of foreign genetic material may also be associated with cancer.
Our comment: Genomes of practically all living organisms are interspersed with pieces of DNA that they have acquired in the evolutionary process. This was not the result of man-made genetic manipulation. There is no scientific evidence whatsoever that spliced genes are more prone to jump out of the genome and into other genomes.
- Horizontal transfer of genes and constructs from the 'Golden Rice' will spread transgenes, including antibiotic resistance genes to bacterial pathogens, and also has the potential to create new viruses and bacteria associated with diseases.
Our comment: This statement has no scientic basis whatsoever. Golden Rice, as it is being distributed to plant breeders around the world, has no antibiotic resistance genes nor viral promoters. And even if that were the case, there would be no reason to believe that undesirable dangers were looming, as we have learned hundreds of millions of times from all those transgenic plants being grown commercially around the world. If we took that argument seriously, then we would have to assume that every piece of DNA is just waiting for an opportunity to invade other organisms to create new forms of life. If we look at this last idea more philosophically, we might say that yes, indeed, DNA has been recreating itself since its first appearance on Earth, giving rise to out huge biodiversity.
These beautiful, healthy and normal looking rice plants are «Golden Rice» growing in the field. The golden colour only show when the grains are milled.
