New approach to detecting changes in GM foodsDoes 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. A new study in the March issue of The Plant Genome demonstrates a potentially more powerful approach to answering them.In research led by Owen Hoekenga a Cornell University adjunct assistant professor scientists extracted roughly 1000 biochemicals or metabolites from the fruit of tomatoes. These tomatoes had been genetically engineered to delay fruit ripening -- a common technique to help keep fruits fresher longer. The researchers then compared this metabolic profile from the GM fruit to the profile of its non-GM variety.Extracting and analyzing hundreds metabolites at once gives researchers a snapshot of the fruit's physiology which can be compared against others.When the scientists compared the biochemicals of the GM tomato and a wide assortment other non-GM tomatoes including modern and heirloom varieties they found no significant differences overall. Thus 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. However the biochemicals related to fruit ripening did show a significant difference -- no surprise because that was the intent of the genetic modification.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. The process is designed to catch instances where genetic manipulation may have affected nutritional quality for example.Moreover comparing a GM variety to diverse cultivars can help scientists and consumers put into context any biochemical changes that are observed. We accept that there isn't just one kind of tomato at the farmer's market. We look for diverse food experiences Hoekenga says. So we think that establishing the range of acceptable metabolic variability [in food] can be useful for examining GM varieties.The process was expensive and the chemistry methods can't yet be used in official safety assessments Hoekenga acknowledges. Making statistical comparisons of metabolic fingerprints is no easy task. In their study Hoekenga's group adapted a style of statistics used in other research.But the techniques don't apply only to tomato. The method can be applied to any plant or crop Hoekenga says. We've made something fundamentally useful that anyone can use and improve on.When crossing parent plants for example breeders often like to track the genes underlying their trait of interest such as resistance to a pathogen. That's because pinpointing offspring that carry the right genes is often faster and easier than examining plants for the trait itself.But sometimes so many genes contribute to a single trait that figuring out which genes are involved in the first place becomes onerous. This is where Hoekenga thinks his style of research and analysis might one day help. We're trying to describe at the biochemical level what might be responsible for a trait. And from that you could extract genetic information to use in breeding.Story Source:The above story is based on materials provided by Crop Science Society of America. Note: Materials may be edited for content and length.Journal Reference: