A new approach to detecting unintended changes in GM foods
Does genetic manipulation causes unintended changes in food quality and composition? Are genetically modified (GM) foods less nutritious than their non-GM counterparts, or different in unknown ways?
Despite extensive cultivation and testing of GM foods, those questions still linger in the minds of many consumers. Now a new study in the March 2014 issue of The Plant Genome demonstrates a potentially more powerful approach to answering them.
In the research led by Owen Hoekenga, a Cornell University adjunct assistant professor, scientists used a water-alcohol solvent to extract roughly 1,000 biochemicals, or “metabolites,” from the fruit of tomatoes they’d genetically engineered to delay fruit ripening. They then compared this metabolic profile from the GM fruit to the profile of its non-GM, parent variety.
Many metabolites, including pigments, amino acids, sugars, and various health-promoting compounds, are known to contribute to fruit quality and nutrition. And extracting and analyzing hundreds of them at once gives researchers a snapshot of the fruit’s physiology—known as the “metabolome”—which can be compared against others. In this way, “metabolomic” analysis is very similar to genomics, where geneticists compare DNA sequence data to understand how genetically divergent different organisms are.
When Hoekenga and his colleagues performed their analysis, they did in fact uncover metabolic differences in the GM fruit relative to its parent, although these changes were mostly seen in biochemicals related to fruit ripening, Hoekenga says. “So that’s part of an intended effect.”
But when the scientists compared the metabolome of the GM tomato with those of a wide assortment of garden, heirloom, and other non-GM tomatoes, they found no significant differences overall. In other words, although the GM tomato was distinct from its parent, its metabolic profile still fell within the “normal” range of biochemical diversity exhibited by the larger group of varieties.
The finding suggests little or no accidental biochemical change due to genetic modification in this case, as well as a “useful way to address consumer concerns about unintended effects” in general, Hoekenga says.
He explains that the FDA already requires developers of GM crops to compare a handful of key nutritional compounds in GM varieties relative to their non-GM parents. Part of biotechnology risk assessment, the process is designed to catch instances where genetic manipulation may have affected nutritional quality, for example.
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