Here's another response published in Nature Biotechnology to the article by Bradord, Strauss et al, arguing that GM (transgenic) crops face a "daunting" array of regulatory requirements which should be relaxed, at least in some cases, to reduce the costs of commercialization.
Bradford, Strauss et al set aside safety concerns related to the process of genetic engineering itself, as well as its unintended consequences, but as in their report 'Genome Scrambling - Myth or Reality?', Allison Wilson, Jonathan Latham & Ricarda Steinbrecher point out that "all particle bombardment transgene insertion events include extensive rearrangements or loss of host DNA as well as insertion of superfluous DNA". Yet these type of extensive mutations "would almost certainly pass unnoticed through both the molecular and phenotypic characterization stages of the regulatory systems of both the European Union and the United States."
For the response of David Schubert, a Professor in the Cellular Neurobiology Laboratory at The Salk Institute, to Bradord, Strauss et al:
Regulatory regimes for transgenic crops
Nature Biotechnology 23, 785 (2005); doi:10.1038/nbt0705-785a
Allison Wilson, Jonathan Latham & Ricarda Steinbrecher
To the editor:
In presenting their justifications for reducing the regulatory burden on transgenic food crops (Nat. Biotechnol. 23, 439_444, 2005), we feel that Strauss and colleagues significantly misrepresent the implications and rationale of our report Genome Scrambling-Myth or Reality? Transformation-Induced Mutations in Transgenic Crop Plants1. Unlike their characterization of our work, we did not specifically "argue for rejection if even a single base pair is changed." In full, our relevant recommendations were that "transgenic lines containing genomic alterations at the site of transgene insertions be rejected" and that "the insertion of superfluous DNA be considered unacceptable."
Leaving aside the fact that a single base pair change may result in serious phenotypic consequences, these recommendations are best viewed in context. As documented in the report, thorough analysis reveals that all particle bombardment transgene insertion events include extensive rearrangements or loss of host DNA as well as insertion of superfluous DNA. Furthermore, a large fraction of even apparently simple Agrobacterium tumefaciens_mediated transgene insertion events also result in large-scale host DNA rearrangement or deletion and superfluous DNA insertion2. For example, loss of 76 kbp of host DNA3 and duplication/translocation of up to 40 kbp of host DNA have been reported at T-DNA insertion sites4.
Widespread use of transgenic crops carrying insertion-site mutations of this magnitude will, in our opinion, lead sooner or later to harmful consequences. Nevertheless, detailed inspection has shown that mutations such as these would almost certainly pass unnoticed through both the molecular and phenotypic characterization stages of the regulatory systems of both the European Union and the United States5, 6, 7, 8.
We do agree with Strauss and colleagues that analysis of the phenotype is the one true measure of safety. However, rigorous assessment only at the phenotypic level is time consuming, expensive and, more importantly, of unproven effectiveness9. In this context, our recommendations for the detection and elimination of transformation-induced mutations from commercial crop plants are conceived as a straightforward and effective way to reduce the probability of unexpected deleterious phenotypes arising in transgenic crop plants and of protecting consumers and others from an unnecessary risk.
1. Wilson, A., Latham, J. & Steinbrecher, R. Genome Scrambling””Myth or Reality? Transformation-induced Mutations in Transgenic Crop Plants. (Econexus, Brighton, UK, 2004). http://www.econexus.info
2. Forsbach, A., Schubert, D., Lechtenberg, B., Gils, M. & Schmidt, R. Plant Mol. Biol. 52, 161 176 (2003).
3. Kaya, H. et al. Plant Cell Physiol. 41, 1055 1066 (2000).
4. Tax, F.E. & Vernon, D.M. Plant Physiol. 126, 1527 1538 (2001).
5. Hernandez, M. et al. Transgenic Res. 12, 179 189 (2003).
6. Windels, P., Tavernier, I., Depicker, A., Van Bockstaele, E. & De Loose, M. Eur. Food Res. Technol. 213, 107 112 (2001).
7. Freese, W. & Schubert, D. Biotechnol. Genet. Eng. Rev. 21, 299 324 (2004).
8. Spok, A. et al. Risk Assessment of GMO Products in the European Union (Bundesministerium fur Gesundheit und Frauen, Vienna, 2004) http://www.bmgf.gv.at
9. Kuiper, H.A., Kleter, G.A., Noteborn, H.P.J.M. & Kok, E.J. Plant J. 27, 503 528 (2001).