Dr. Mae-Wan Ho, Director, Institute of Science in Society, UK
I would like to comment on points raised in Aventis’ Oral Submission made on 29 May 2002 [1]. I address my comments specifically to paragraphs 10.4 to 10.16, which Mr. Alun Alesbury considers to be new evidence countering alleged instability of CHARDON LL, and to paragraphs 10.19 to 10.20, which concerns evidence on the CaMV 35S promoter I had presented to this hearing [2, 3]. I would also like to take this opportunity to update on the evidence against the proposed addition of Chardon LL to the UK National List, which has emerged since the hearing was adjourned in October 2000.
Paragraphs 10.4 to 10.16 (p. 19 -22, ref. 1) purport to describe the process whereby event T25 containing the genetic modification that produces the enzyme phosphinothricin acetyltransferase (PAT) in maize, was selected from the primary transformants, resulting in a T25 inbred line that was then repeatedly backcrossed to the non-GM variety for a number of generations. Exactly how the crosses were made was not stated. There are numerous assertions throughout the paragraphs that the line(s) are stable, for which no evidence, whatsoever, was presented.
There are no data to support the stability of the original T25 "inbred line". It is not even stated how many generations that "line" has been perpetrated. So long as this "inbred line", and the subsequent repeatedly backcrossed line, referred to as "converted inbred", require selection with the herbicide glufosinate-ammonium (GA), then the lines are clearly either not uniform or not stable, or both. Otherwise, practically all plants would be expected to be GA-tolerant.
Paragraph 10.7 states, "during every generation of the backcross process, GA was sprayed before flowering, to identify the segregating plants carrying the GA tolerance, and to ensure that all plants not expressing the trait could not contribute to the progeny." But without counting the number of GA-tolerant versus GA-susceptible plants, and without performing the necessary molecular analyses, it is not possible to distinguish "segregating plants" - progeny derived from the non-GM plants and never having had the transgene at all - from GM plants that have simply gone unstable.
Paragraph 10.10 states, "Since the last backcrossing step, the converted inbred had undergone at least 5 generations of self-crossing, without giving reason to doubt the line’s lack of expression or stability. In all multiplication steps of the T25 line, GA was applied before flowering so any plants not expressing the trait would not contribute to progeny. The frequency of "off types", (looking at their morphology or lack of expression of the GA tolerance gene), was very low, especially as compared to the norm in the seed industry for pre-basic and basic seed." But if the backcross had really generated a "converted inbred" line, there should be no GA-susceptible plants remaining, if the line were uniform and stable. And without numerical and molecular data, we cannot know if the line fell within the accepted "norm" or not.
More to the point, stable expression of the trait is no guarantee of genetic stability. To prove genetic stability requires characterisation by molecular analyses to demonstrate that both the structure and location of the transgenic insert(s) remain unchanged in successive generations. No such data have been presented.
Towards the end of last year, the GA-tolerant oilseed rape crop, planted as part of the Farm Scale Evaluation in Black Isle near Munlochy, suffered extensive herbicide damage after it was sprayed with GA [4]. That was a sign of massive transgenic instability in another GA-tolerant crop produced by Aventis, and the company has yet been unable to offer a counter explanation.
The new European Directive for deliberate release 2001/18 /EC specifically requires molecular data documenting that the GMO is genetically stable.
In order to prove that the lines are stable as claimed, Aventis must now present all past and present molecular data, and provide samples for independent analyses.
Paragraphs 10.19 to 10.20 attempt to discredit the evidence on CaMV promoter I had submitted to the hearing, which consisted of at least three papers I and my colleagues published in a scientific journal [5-7]. However, Aventis referred to the first paper only, but not the other two that had answered all scientific criticisms raised, as I pointed out in my previous submissions [2, 3].
Instead of dealing with the scientific criticisms, the company has chosen to cite copiously from an ‘analysis’ by a science journalist, not a scientist, published under "Business and regulatory news" in the journal Nature biotechnology. That ‘analysis’, concocted entirely of hearsay and opinions, and contained such defamatory, libellous statements that the journal had to give us a right to reply when challenged. Our reply was published [8], along with the journalist’s ‘apology’ that he had failed to cite our rebuttal, but he attacked us yet again. This time, Nature biotechnology refused to print our reply, which appeared elsewhere [7].
Our claims that "CaMV promoter may be structurally unstable and prone to horizontal gene transfer and recombination" are based on extensive reviews of existing scientific findings, some of which emerged long after the promoter had been widely used. A key evidence that provoked us to write the review was the discovery of a ‘recombination hotspot’ in the promoter by at least two groups of researchers. In the course of our debate, we also discovered that the promoter is active in species across the entire living world, including human cells [7]. Our critics appeared not to know that. Aventis too, was ignorant, as were two experts invited to the recent public hearing conducted by ACRE [9].
Two years later, one of the research groups that had discovered the CaMV 35S promoter recombination hotspot called for the promoter to be phased out in the internal report of the John Innes Centre [10], on account of the structural instability it causes. But structural instability would indeed make it prone to horizontal gene transfer and recombination, as we have pointed out.
Last November, a paper published in Nature [11] reported that Mexican maize landraces growing in remote regions have been contaminated by transgenes. The paper is now at the centre of a storm whipped up by scientists supporting biotech, who are criticising it for ‘poor methodology’. This led to a retraction by Nature, which is unprecedented for a paper that has not been proved wrong or fraudulent. The critics are not contesting the fact that transgenic contamination has occurred and that the CaMV 35S promoter has been found in the landraces. In fact, the Berkeley researchers who wrote the original report were able to present new data firming up their conclusion that transgenic contamination in the form of CaMV 35S promoter had occurred. What their critics are contesting is the form in which the promoter has entered the landraces’ genomes [12].
The researchers claimed to have found that the promoter in the landraces’ genomes is linked, not to the original transgenes, but to a variety of other DNA sequences. This is as though the promoter has broken off and joined up at random, or as stated by one of the critiques, "fragmenting and promiscuously scattering throughout genomes". This, the critics are strenuously denying.
But that is far from unexpected, in view of the ‘recombination hotspot’ associated with the CaMV 35S promoter, discovered years after transgenic crops containing the promoter has been widely released. Crucial molecular data that could settle this dispute either do not exist, or are hidden under ‘commercial confidentiality’. Three companies, Monsanto, Novartis and Aventis have all created transgenic maize containing the CaMV 35S promoter. But without the ‘event-specific’ molecular data, it is difficult to find out which of the transgenic maize has contaminated the landraces.
I repeat, the companies must provide both past and present molecular data on their transgenic lines, and submit samples for independent analysis. It is of interest that when Monsanto’s Roundup Ready soya was subjected to analysis [13], the transgenic insert was found scrambled, as was the host genome at the site of insertion. And a DNA fragment of more than 500 basepairs of unknown origin is also present. None of that was reported in the company’s original application submitted for commercial approval.
The new evidence that has emerged has only strengthened my objections. I remain strongly opposed to placing Chardon LL on the National Seed List.
Article first published 14/06/02
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