Prof Schubert replies to Bradford et al (1/12/2005)

Well worth reading in full - even the summary at the end!

Prof Schubert is responding once again to Bradford et al who have been arguing that the regulation of GM food crops should be reduced or eliminated, based upon the assumption that the products of genetic engineering are no different than those produced by classical plant breeding.

Note also the reference to Prof Guy Cook's must-read book "Genetically Modified Language".
http://www.lobbywatch.org/p1temp.asp?pid=68&page=1

EXCERPTS: I, and hundreds before me, pointed out that [the claim that GM plants are no different from classically bred plants] is unambiguously not the case. I used specific references to show that many of their statements were misrepresentations of scientific fact. In their reply to my comments they used several new rhetorical techniques in addition to the standard ones such as taking statements out of context and misquoting sources. Of greatest concern is the new lexicon that has been evolving in the plant biotechnology industry over the last decade...

Perhaps the most curious aspect of all is that plant biotechnology is complaining about a regulatory system that was written by their lawyers (Eichenwald et al., 2001) and at least with respect to the FDA is voluntary and lacks safety testing requirements altogether (Gurian-Sherman, 2003; Freese & Schubert, 2004). Although they have what they asked for, they are still complaining about it.
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RESPONSE TO BRADFORD et al.
David Schubert
Professor
Salk Institute
La Jolla, CA 92037

The following are some comments on the rebuttal (Bradford et al., 2005a) to my critique (Schubert, 2005) of a manuscript (Bradford et al., 2005b) that appeared in Nature Biotechnology. In their original article, Bradford and colleagues argue that the regulation of transgenic food crops should be reduced or eliminated, based upon the assumption that the products of genetic engineering (GE) are no different than those produced by classical plant breeding. I, and hundreds before me, pointed out that this is unambiguously not the case. I used specific references to show that many of their statements were misrepresentations of scientific fact. In their reply to my comments they used several new rhetorical techniques in addition to the standard ones such as taking statements out of context and misquoting sources. Of greatest concern is the new lexicon that has been evolving in the plant biotechnology industry over the last decade in order to deceive the less technically educated into believing that there should be no concern about GE food crops because, as they argue, the outcomes are identical to those obtained with standard breeding techniques. Since they cannot ignore the overwhelming evidence that GE is highly mutagenic, they are instead trying to equate GE with normal breeding by redefining the fundamental meaning of some relevant terminology. An excellent book entitled "Genetically Modified Language", written by a linguist, Guy Cook, shows how the plant biotechnology community is misusing language to promote themselves (Cook, 2005). As described in detail below, examples of "genetically modified language" are abundant in the rebuttal by Bradford et al. of my critique.

1. Lack of precision. The initial response of Bradford et al. in defense of the unambiguously high rate of mutagenesis in GE crops is a perfect example of how plant biotechnology is attempting to change the technical definitions of genetics for the purpose of self promotion. They state that "conventional breeding is based on essentially random induction or assembly of mutations", followed by "imprecise natural recombinations between genomes". Thus, they are equating recombination with mutagenesis, and so, by extension, GE with natural breeding. This is not only scientifically incorrect but exceptionally deceptive.

Recombination occurs with high fidelity between allelic genes. There is no mutagenesis involved in the standard recombination event, for if there were, there would be no such thing as a stable species of plant or animal. This section of the critique by Bradford et al. concludes by stating "changes accompanying GE may occur, but are irrelevant so long as the expected phenotype is produced". The problem here is that they redefine phenotype to suit their purposes. In general scientific usage phenotype refers to all traits, while these authors use 'phenotype' in both their original paper and their rebuttal to mean solely agricultural characteristics, ignoring other traits that might be caused by genotypic changes from GE. The tests used to assay unintended changes to phenotype are, to date, quite limited. The legitimate debate is whether these limited tests are adequate. Will an assay to detect changes in yield of peas detect an increase in rotenone or other harmful secondary metabolites?

2. Basic research vs. cultivar development. The discussion in this section is completely meaningless, for in my critique I was concerned about toxicological traits, not agronomic ones, and unless they can establish a causal link between plant height or yield and potentially toxic secondary metabolites, agronomic traits are not relevant to the health and safety issue.

3. Mutagenized cultivars. Since both the original Bradford paper and my critique deal only with US regulatory policies, I specifically stated that I was discussing food crops in the US. The manuscript by Ahloowalia et al. (Ahloowalia et al., 2004) lists all of the registered crops (non-food as well as food) in the world that have a mutagenized parent. The "2,275 varieties of 175 species" referred to by Bradford et al. include flowers and many other non-food crops, and the vast majority are not now and never were used commercially. As I stated in my critique of the food crops, the only one listed by Ahloowalia et al. as a commercial crop in the US is the sunflower. The major cultivars of the US crops of corn, soybeans and wheat are not derived by mutagenesis. The implication that I misrepresented the Ahloowalia article is therefore incorrect. Indeed, it would be of interest to many if Bradford et al. could list and document those vast numbers of crops in the US food supply that they claim are derived by mutagenesis.

4. Wide crosses. I agree that "genetic changes often accompany wide crosses". I don't doubt that genetic changes always occur during any breeding procedure. Indeed, that is the point of sexual reproduction. However, the question is whether or not those changes that do occur are the same as those caused by GE? First, Bradford et al. again try to equate recombination with mutagenesis which, as discussed above, is not correct. Knowing this group's propensity for "genetically modified language" I specifically pointed out the difference in my original critique. Second, their "large body of evidence" supporting the claim that wide crosses are mutagenic is rather paltry, and certainly does not justify


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