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Unintended Effects of Genetic Manipulation
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Flavonol-enriched tomatoes had altered levels of at least fifteen other substances.

Manipulated Organism: Tomato (Lycopersicon esculentum mill.).

Inserted Transgenes: LC and C1 regulatory genes from maize; promoter not mentioned.

Goal: Transgenic tomatoes that overexpress the LC and C1 genes and therefore produce more flavonols (flavonoid glycosides), which are antioxidants. This study investigated, through metabolic profiling, whether the genetic manipulation brings about other changes in substances as well.

Intended Effect: There was a greater than ten-fold increase in the amount of flavonols.

Unintended Effects: The amounts of at least fifteen other substances were altered (in statistically significant amounts). For example, there was two to three times less citric acid, sucrose, and phenylalanine, and two to three times more trigonelline (an alkaloid) in the transgenic tomatoes.

Additional Comments: The transgenic plants and the nontransgenic controls were "grown side-by-side in a glass house under hydroponic conditions with identical treatments (nutrients, light, etc.)." The authors call the changes in the amounts of nontarget substances "minor" since they were within the "natural variation that would be observed in a field-grown crop." Of course, this conclusion assumes that the transgenic plants, which show these differences under controlled conditions, would vary under field conditions in the same way as unmanipulated plants. There is no evidence that this is the case.

Source: Le Gall, G., I. Colquhoun, A. Davis, G. Collins et al. (2003). "Metabolite Profiling of Tomato (Lycopersicon esculentum) using 1H NMR Spectroscopy as a Tool to Detect Potential Unintended Effects Following a Genetic Modification," J. Agric. Food Chem. vol. 51, pp. 2447-56.

Author Affiliations: Institute for Food Research, UK (see below), and Unilever Research, UK.

Funding: Institute of Food Research, UK (according to its website: a "not-for-profit company with charitable status" sponsored by the Biotechnology and Biological Sciences Research Council, which is the UK's principal public funder of basic and strategic biological research) and Unilever Research (Pharmaceutical Company), UK.

Product Status: Not on the market as of 2008.

Copyright 2008 The Nature Institute.

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