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Controversial engineered maize given clean bill of health
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Maize toxicity claims roundly rebuffed MONSANTO, the giant of genetically modified crops, has for the first time been forced to release raw data from toxicology studies it carried out on three strains of its modified maize. An external analysis of the data claims it shows that eating the maize could result in damage to the liver and kidneys, but this has been dismissed as unsupportable by a government agency and independent toxicologists. With legal help from Greenpeace and the Swedish Board of Agriculture, researchers at the Committee of Research and Information on Genetic Engineering, a French anti-GM lobby group, forced Monsanto to release the data from studies in which rats were fed with the three varieties of maize for three months. Two of the maize varieties, MON 810 and MON 863, contain genes for the bacterial Bt protein, which protects against corn borer larvae. The third, NK 603, is resistant to the weedkiller glyphosate. All are widely grown in the US, while MON 810 is the only GM crop grown in Europe, mainly in Spain. The re-analysis of the data, led by Gilles-Eric Séralini at the University of Caen in France, concludes that the rats showed statistically significant signs of liver and kidney toxicity (International Journal of Biological Sciences, vol 5, p 706).
With each of the three strains of maize, researchers say they found unusual concentrations of hormones and other compounds in the blood and urine of the tested rats, suggesting each strain impaired kidney and liver function. By the end of the trials, the female rats that were fed MON 863 had elevated blood-sugar levels and raised concentrations of fatty substances called triglycerides. Both are potential precursors of diabetes, according to Séralini. And there were further signs that the kidneys of rats fed NK 603 were impaired, he says. “What we’ve shown is clearly not proof of toxicity, but signs of toxicity,” says Séralini. “I’m sure there’s no acute toxicity, but who’s to say there are no chronic effects?” He wants longer studies on more species to check for such effects. Unsurprisingly, Monsanto has refuted the findings, saying they do not demonstrate that there is any risk to the consumer. France’s High Council of Biotechnology, too, has said that the study provides no new evidence of toxicity from the three maizes. Independent toxicologists contacted by New Scientist said Séralini’s analysis overplays the importance of minor variations that most experienced toxicologists would consider to be random background noise. The study did not address the environmental concerns associated with GM crops, which have led six European countries to ban MON 810. Andy Coghlan ■
MICHAEL KAPPELER/DDP/GETTY
brain and the oil droplet do share some fundamental attributes, in particular they both respond to their environment to minimise errors. This ties in with Bayesian brain theory, which pictures our brains as attempting to understand the world by observing the environment and making, then improving, predictions about what will happen next. Friston is working on a unified theory of the brain (New Scientist, 31 May 2008, p 30) that mathematically describes how the brain continually improves its predictions by observing its environment and minimising errors. He sees “deep similarities” between his theory and the droplet’s movement. As the droplet moves towards the exit it is moving towards a state of chemical equilibrium, where it has minimised its free energy. Work on artificial neural networks has shown that the same principles apply to these networks: by minimising the difference between the predictions a network makes and what it actually senses happening, –Just following the cues– the network is also driven towards equilibrium. Friston is now It’s a powerful idea that is showing how the equations that filtering into theories about govern neural networks and artificial intelligence. Rolf Pfeifer thermodynamic systems apply at the University of Zurich in to real brains. Switzerland is exploring how to The bottom line is that the “outsource” some of the cognitive “dumb” droplet is simply obeying load of artificially intelligent fundamental principles. But systems. He points out evidence because it is using exceptionally that the way our knees absorb the ordered information in the energy of a jump is controlled by environment along the way, the material properties of the leg it moves “in an apparently itself: the reactions happen too purposeful way”, Friston says. quickly to be controlled by the None of this, of course, justifies brain or even a reflex. Through calling Grzybowski’s oil droplet careful choice of materials, Pfeifer “intelligent”. But it does is now applying that idea in his suggest that by highlighting the robot creations by designing body importance of the environment, parts that are capable, to some his maze experiment may have degree, of autonomously reacting hit on a fundamental connection to their environment. between apparently intelligent Karl Friston, a neuroscientist behaviour at all levels: the at University College London, ability to read and respond to goes further. He says the human environmental cues. ■
–Modified maize raises fears– 23 January 2010 | NewScientist | 9
Maize toxicity claims roundly rebuffed MONSANTO, the giant of genetically modified crops, has for the first time been forced to release raw data from toxicology studies it carried out on three strains of its modified maize. An external analysis of the data claims it shows that eating the maize could result in damage to the liver and kidneys, but this has been dismissed as unsupportable by a government agency and independent toxicologists. With legal help from Greenpeace and the Swedish Board of Agriculture, researchers at the Committee of Research and Information on Genetic Engineering, a French anti-GM lobby group, forced Monsanto to release the data from studies in which rats were fed with the three varieties of maize for three months. Two of the maize varieties, MON 810 and MON 863, contain genes for the bacterial Bt protein, which protects against corn borer larvae. The third, NK 603, is resistant to the weedkiller glyphosate. All are widely grown in the US, while MON 810 is the only GM crop grown in Europe, mainly in Spain. The re-analysis of the data, led by Gilles-Eric Séralini at the University of Caen in France, concludes that the rats showed statistically significant signs of liver and kidney toxicity (International Journal of Biological Sciences, vol 5, p 706).
With each of the three strains of maize, researchers say they found unusual concentrations of hormones and other compounds in the blood and urine of the tested rats, suggesting each strain impaired kidney and liver function. By the end of the trials, the female rats that were fed MON 863 had elevated blood-sugar levels and raised concentrations of fatty substances called triglycerides. Both are potential precursors of diabetes, according to Séralini. And there were further signs that the kidneys of rats fed NK 603 were impaired, he says. “What we’ve shown is clearly not proof of toxicity, but signs of toxicity,” says Séralini. “I’m sure there’s no acute toxicity, but who’s to say there are no chronic effects?” He wants longer studies on more species to check for such effects. Unsurprisingly, Monsanto has refuted the findings, saying they do not demonstrate that there is any risk to the consumer. France’s High Council of Biotechnology, too, has said that the study provides no new evidence of toxicity from the three maizes. Independent toxicologists contacted by New Scientist said Séralini’s analysis overplays the importance of minor variations that most experienced toxicologists would consider to be random background noise. The study did not address the environmental concerns associated with GM crops, which have led six European countries to ban MON 810. Andy Coghlan ■
MICHAEL KAPPELER/DDP/GETTY
brain and the oil droplet do share some fundamental attributes, in particular they both respond to their environment to minimise errors. This ties in with Bayesian brain theory, which pictures our brains as attempting to understand the world by observing the environment and making, then improving, predictions about what will happen next. Friston is working on a unified theory of the brain (New Scientist, 31 May 2008, p 30) that mathematically describes how the brain continually improves its predictions by observing its environment and minimising errors. He sees “deep similarities” between his theory and the droplet’s movement. As the droplet moves towards the exit it is moving towards a state of chemical equilibrium, where it has minimised its free energy. Work on artificial neural networks has shown that the same principles apply to these networks: by minimising the difference between the predictions a network makes and what it actually senses happening, –Just following the cues– the network is also driven towards equilibrium. Friston is now It’s a powerful idea that is showing how the equations that filtering into theories about govern neural networks and artificial intelligence. Rolf Pfeifer thermodynamic systems apply at the University of Zurich in to real brains. Switzerland is exploring how to The bottom line is that the “outsource” some of the cognitive “dumb” droplet is simply obeying load of artificially intelligent fundamental principles. But systems. He points out evidence because it is using exceptionally that the way our knees absorb the ordered information in the energy of a jump is controlled by environment along the way, the material properties of the leg it moves “in an apparently itself: the reactions happen too purposeful way”, Friston says. quickly to be controlled by the None of this, of course, justifies brain or even a reflex. Through calling Grzybowski’s oil droplet careful choice of materials, Pfeifer “intelligent”. But it does is now applying that idea in his suggest that by highlighting the robot creations by designing body importance of the environment, parts that are capable, to some his maze experiment may have degree, of autonomously reacting hit on a fundamental connection to their environment. between apparently intelligent Karl Friston, a neuroscientist behaviour at all levels: the at University College London, ability to read and respond to goes further. He says the human environmental cues. ■
–Modified maize raises fears– 23 January 2010 | NewScientist | 9