Seeking clarity in the debate over the safety of GM foods

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A more rigorous analysis of the debate over GM versus non-GM crops is now needed. A fundamental flaw in most arguments (for example, the debate on substantial equivalence1,2) is the erroneous treatment of all genetically modified (GM) plants as one homogeneous group. This distorts arguments and weakens reasoning. It is time to introduce a classification of the distinctive types of GM crops. I propose the use of three classes:

  1. 1

    ‘Wide transfer’, referring to the movement of genes from organisms of other kingdoms into plants;

  2. 2

    ‘Close transfer’, referring to movements of genes between species of plants; and

  3. 3

    ‘Tweaking’, referring to the manipulation of levels or patterns of expression of genes already present in a plant's genome.

Genetic modification, in its strictest meaning, has been performed for 10,000 years, including notably gross manipulations such as the development of hexaploid wheat and triticale. Consequently, I think it would also be sensible (and politically appropriate!) to refer to GM crops generated using modern biotechnology as ‘new GM crops’, as distinct from the ‘old GM’ of traditional breeding technologies.

Use of such terminology will throw into relief some of the more extreme claims made by both sides of the argument. For example, the use of ‘substantial equivalence’ (as employed for conventional crops) is most likely to be sufficient for crops developed using ‘close transfer’ and ‘tweaking’, as the results of these manipulations are unlikely to be different from processes used by traditional breeders. However, the introduction into the food chain of significant amounts of novel proteins by ‘wide transfer’ may well require more thorough testing, as for the introduction of a drug. If such tests were introduced only for plants generated by wide transfer, then the obvious objections to this suggestion raised by Anthony Trewavas and C. J. Leaver2 would not apply.

Use of a refined categorization of the new GM crops would focus arguments and facilitate more balanced conclusions in a currently unnecessarily polarized debate.


  1. 1

    Millstone, E., Brunner, E. & Mayer, S. Nature 401, 525–526 (1999).

  2. 2

    Trewavas, A. & Leaver, C.J. Nature 401, 640 (1999).

  3. 3

    Food & Agriculture Organization/World Health Organization Biotechnology and Food Safety: Report of a Joint FAO/WHO Consultation (FAO, Rome, 1997).

  4. 4

    Gasson, M.J. Nature 402, 229 (1999).

  5. 5

    Getz, J. M., Venecil, W. K. & Hill, N.S. The 1999 Brighton Conference 8C-6, 835–840 (British Crop Protection Council, Farnham, 1999).

  6. 6

    Burke, D. Nature 401, 640–641 (1999).

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Tester, M. Seeking clarity in the debate over the safety of GM foods. Nature 402, 575 (1999) doi:10.1038/45054

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