Institute of Science in Society
Director: Dr. Mae-Wan Ho
Date: 28 February 2002
To: Scottish Parliament Petitions Committee
From: Dr. Mae-Wan Ho
I am writing to support the Munlochy Vigil petition, to call for an immediate end to GM OSR trials in Scotland and for a full Parliamentary debate, with a free vote on the issue of GM crops in Scotland. I wish to state my reasons for opposing the introduction of GM crops to the UK in the farm scale evaluations, in particular to Aventis’ GM oilseed rape, which is being field-tested in Scotland.
Since the commercial growing of GM crops in 1994, there have been many university-based studies documenting that they have lower yields, perform poorly in the field, use more pesticides and result in reduced profits for farmers. The details are contained in a new report [1] from the Institute of Science in Society (ISIS), of which I am Director.
This is done through patenting of GM crops and genes and draconian measures to prevent farmers from saving seeds, through GM crops linked to herbicides sold by corporations, and worst of all, through crops engineered to make the plants or seeds sterile. Aventis’ GM oilseed rape is engineered to be male sterile, for the stated reason of producing ‘high-yielding’ hybrid; but the real reason is to protect corporate patents.
ISIS has covered the hazards of GM crops extensively, and is including several reprint collections for your perusal [2-4]. Genes incorporated into GM crops are typically from bacteria and viruses that cause diseases, and include antibiotic resistance marker genes that could make infectious diseases untreatable. These genes and gene products have never been part of the food chain of either human beings or many of the animals that feed on the plants.
The endotoxins isolated from the soil bacterium Bacillus thuringiensis (bt) are known to be harmful to beneficial insects such as the lacewings and endangered species such as the monarch butterfly, as well as to rodents.
The barnase gene used for making male-sterile lines, such as Aventis’ GM oilseed rape, is a universal cell poison that requires a very specific antidote, it has been shown to be toxic to the rat kidney and to human cell lines.
Glufosinate herbicide, used with many GM crops including Aventis GM oilseed rape, is known cause birth defects [5-7] and to damage nerve cells [8,9]. It has also been found to harm predatory insects and mites [10] and caterpillars of the skipper butterfly Calpodes ethlius [11]. This will have knock-on effects on the survival of birds. The field trials in Scotland are close to some of the most precious wild-life preserves. The run-off from Roskill Farm, for example, goes directly into the Munlochy Bay, thereby contaminating the drinking water for both wildlife and human beings.
A 1998 study in Canada revealed that herbicide-tolerant oilseed rape rapidly evolved into superweeds through accumulating multiple herbicide-tolerant traits - a phenomenon referred to as ‘gene-stacking’ [12]. A new report by English Nature [13] draws attention to the same findings in 11 further fields in Alberta, Canada, and also in field trials in the United States. It concludes that such gene-stacking for multiple herbicide tolerances are inevitable, and would necessitate using additional herbicides to control these volunteers.
The safety of GM crops was strongly contested by scientists and others during the Chardon LL hearing held in the UK the year before last. Perhaps most relevant to the issue of safety is the genetic stability and uniformity of GM crops. The public hearing on T25 was suspended over a year ago when it was found not to have passed the required EC test for Distinctiveness, Uniformity and Stability (the DUS test), as I pointed out when giving evidence to the hearing [14].
The new EC Directive on deliberate release (Directive 2001/18) requires strict molecular evidence of genetic stability, which is also necessary for establishing the identity of the transgenic line and to ensure traceability. The best-kept secret of GM crops is that they are not stable.
The severe stunting of the GM oilseed rape in Roskill Farm subsequent to the application of the glufosinate herbicide (munlochyvigil@tiscall.co.ul) is an example of such instability. The glufosinate-tolerant GM crop has apparently lost its ability to tolerate the herbicide, and we urgently need to know why, for safety reasons.
There is a large literature on gene silencing, in which the transgenes remain in the genome, but are not expressed. More serious, from the safety point of view, is structural instability, the tendency for the transgenic DNA to come loose, to rearrange or become lost in part or in whole in successive generations (see [4,15]). This could change the transgenic line in unpredictable ways in terms of health and environmental risks. And it will increase the chance of transgenic DNA being taken up by unrelated species to make new combinations with their genetic material. That is referred to as horizontal gene transfer and recombination. Transgenic DNA can spread to every species that interacts with the transgenic plant, in the soil, in the air, in the mouth and gut and the respiratory tracts of animals including human beings.
New viruses and bacteria that cause diseases could be generated, and antibiotic resistance marker genes could spread to the pathogens. Transgenic DNA may also get into human cells and insert into the human genome; and a large body of evidence from so-called gene therapy experiments have amply demonstrated this does take place [16]. The constructs used in gene therapy are very similar to those used in transgenic plants, and one main ‘side-effect’ of transgenic DNA inserting into human genome during gene therapy is cancer.
Despite that, our regulators have not required biotech companies to provide molecular evidence of stability. ACRE’s latest guidelines for industry put out for public consultation asks industry to provide molecular evidence of genetic stability over one generation only [17], which is derisory. We need data for at least five successive generations [18]. No such data have come forward from the companies. On the contrary, companies have been allowed to hide under ‘commercial confidentiality’. And the available information provided is vague, contradictory and sometimes wrong, as in the case of Aventis’ GM oilseed rape.
Transgenic DNA is different from natural DNA, and is more likely to take part in horizontal gene transfer and recombination for the following reasons.
In addition to the usual instability, certain constructs and sequences in the transgenic DNA can make it even more unstable, and hence more prone to horizontal gene transfer and recombination. These are as follows:
MS8/RF3, which is being field tested in Scotland, is a genetically modified oilseed rape system for producing hybrid seeds. As stated earlier, it engineers the crop to be male sterile in order to protect corporate patents. Its gene products are hazardous.
It is very difficult to get a clear picture of the genetic modification because crucial molecular information is withheld from the public under ‘commercial confidentiality’, while the available information is vague, contradictory and even wrong.
As far as can be gathered, the system uses a gene for male sterility in the MS8 line, and a gene that restores male fertility in the RF3 line. Male sterility is achieved by a gene coding for barnase, which, as already mentioned, is a cell poison. It breaks down RNA, an intermediate in the expression of all genes. Fertility is restored by a gene coding for barstar, a specific inhibitor of barnase. Both barnase and barstar genes are derived from the soil bacterium, Bacillus amyloliquefaciens, and are placed under the control of a promoter (pTA29, from tobacco plant) that is expressed, in principle, only in the layer of cells surrounding the pollen sac during anther development. The expression of barnase kills the cells and blocks anther development in the MS8 line. When these plants without anthers are crossed with the line expressing the barstar gene (RF3), barnase is inactivated, and anther development proceeds, so the hybrid is fertile.
MS8, on account of being male-sterile, must always be fertilised by other lines. So, how can such a ‘line’ be maintained? The answer, according to some documents submitted, is that the barnase and barstar genes are both linked to a selective marker, phosphinothricin acetyltransferase gene (pat), originating from the soil bacterium Streptomyces hygroscopicus. It confers tolerance to glufosinate herbicide, which, as described above, not only kills all plants, but harms many animals including human beings.
However, in a letter [34] written in response to my enquiry, the Scottish Executive stated that the RF3 line was not tolerant to glufosinate, ie, the barstar gene was not linked to the pat gene.
In the documents submitted to the Scottish Executive, the pat gene is shown to be under the control of the cauliflower mosaic virus (CaMV) 35 S promoter (albeit in another line, though the implication is that the same construct is used for MS8/RF3). In applications to DEFRA for the same, ie MS8/RF3, the gene is stated to be under the control of another promoter.
In the documents submitted to the Scottish Executive, one criterion of genetic stability was stated to be segregation of two independent genes according to the ratio of 3:1, which is a howler, as two independent genes segregating, if both heterozygotes were dominant, would be 15:1. This highlights the frequent abuse of Mendelian ratios. Failure to find significant deviations from Mendelian ratios does not imply Mendelian inheritance, much less is it a criterion of genetic stability, particularly as the status of the parental line is not independently ascertained. Aventis has admitted Mendelian ratios do not indicate genetic stability during the recent ACRE public hearing on T25 GM maize [35].
By applying the glufosinate herbicide, plants not carrying the male sterility gene will be eliminated from the MS8 line. MS8 is therefore a permanent hybrid, probably maintained by always crossing with RF3, with non-hybrid plants eliminated by glufosinate.
In that case, MS8/RF3 hybrid will spread the male sterility gene through its pollen. As the barstar and barnase genes are not linked together, some of the pollen will be spreading the male sterility gene by itself. This could have large effects on non GM oilseed rape varieties as well as on wild relatives. Another casualty will be bees and human beings consuming honey, if the barnase gene became expressed as a result of horizontal gene transfer and recombination.
Of course, if MS8/RF3 is genetically unstable, as suggested by its failure to tolerate glufosinate in the Munlochy field trial, then all of its transgenic DNA could be taking part in horizontal gene transfer and recombination. Horizontal gene transfer is not just a theoretical possibility.
Transgenic DNA from GM plants has been found to transfer to soil bacteria [36]. The possibility of transfer to bacteria in the mouth and gut of animals was suggested in laboratory investigations funded by the UK government [3]. But ACRE has ignored the evidence by a selective interpretation of the scientific evidence that seems to me contrary to both the precautionary principle and good science [37].
GM crops should be firmly rejected as being both unethical and unsafe for health and the environment. On the contrary, Scotland should be supporting and promoting its thriving organic agriculture. There is now plenty of evidence that sustainable, organic agriculture is working all over the world [1]. GM crops are definitely not needed to feed the world. New research reveals that in many of the poorest African countries on the borders of the Sahara desert, introduction of integrated farming, mixed cropping and traditional water conservation methods are pushing back the desert [38] and increasing per capita food production several fold, keeping well ahead of population growth.
Article first published 28/02/02
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