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It is most desirable that people who are seriously concerned about the risks of transgenic crops express their fears using concrete and solid arguments, in their own interest, because otherwise they might be missing great opportunities without a reason. Factual argumention can be dealt with, either by addressing the perceived 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. These preudo-scientific reports are then cited in a circular fashion, and sadly, they spread very quickly and become credo, based purely on them being repeated in numerous fora.
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 about their roots
and end up entangled in futile politics and sensationalist stunts, with fundraising and grooming their own image becoming the sole reason of being. The negative impact of these actions has
been well described by Mr Moore in a recent article in the Denver Post entitled «
Extreme Agendas Harmful»
.
- 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.
Reply: 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 can carry out.
- The gene constructs are new, and have never existed in billions of years of evolution.
Reply: 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 one-billion years and that not one single organism has remained unchanged over time.
- Unpredictable by-products have been generated due to random gene insertion and functional interaction with host genes, which will differ from one plant
to another.
Reply: 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 caluiflower 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.
Reply: The original versions of Golden Rice contained a CaMV promoter sequence, 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, as it is 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.
Reply: The transgene has been shown to be stable over several generations. The same applies to various gene constructs being commercially used all over the world in over 100-million hectares of agricultural land, 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.
Reply: 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.
Reply: 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 treatment of humans for that same reason (see also above). Moreover, the 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 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.
Reply: Horizontal gene transfer are natural events that occur at an extremely low rate. There is no reason why the Golden Rice genes should be preferentially transferred over 30-thousand-plus other genes in the genome, and if that happened those 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, it will be degraded in the ground at the same rate as the remaining genomic DNA.
- 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.
Reply: This study was widely publicised by opponents of GM technology, but eight years later the study has not found its way into any scientific peer-reviewed publication. Be reminded at this point that the gene studied in that case was that of a herbicide-metabolising gene commonly found in field bacteria. The bees in the study collected the pollen in an open field, which probably explains the source of the bacteria carrying the gene.
- 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.
Reply: Genomes of practically all living organisms are interspersed with pieces of DNA that they have acquired along evolution. 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.
Reply: This statement has no scientic basis. 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. By the same token,we could argue that human DNA was dangerous because it could be taken up by microorganisms that could misuse it to disguise themselves as being body-own cells.
![]() «Golden Rice» growing in the field and looking like … rice». |
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