An ancient ear of corn shows that farmers made drastic genetic modifications to corn at least 4,400 years ago.

Early corn farmers in Mexico manipulated corn's genetic makeup through selective breeding, effectively changing a grassy weed with seeds that could not be chewed into something edible -- and they did it quickly, not over many generations, the researchers say.

Researchers in Germany and the United States identified the genetic modifications by extracting DNA from 4,400-year-old ears of corn. The study results appear to bolster the argument that genetically modified crops are not dangerous because farmers have been creating them for thousands of years. And plant biologists say the changes biotech companies are making in plants today are actually much smaller than those discovered in the new study published in the Nov. 14 issue of Science.

"Changes being made today are probably much smaller than the ones that changed a wild grass with very hard seeds to one that is edible and useful for people," said Nina Fedroff, a plant biologist at Penn State University, who wrote a perspective that accompanied the Science study. "As far as a general hazard, (modern day genetic modifications) are much less hazardous than what people have done for most of the century."

The changes scientists make using molecular biology are tiny, she said, compared with the modifications that dramatically changed the appearance and taste of corn 4,400 years ago. Scientists can manipulate a single gene, while selective breeding is much less precise.

But critics counter by saying that single genes inserted into different species can behave in unpredictable ways.

"What (researchers are) doing with genetic engineering today is crossing species boundaries," said Craig Culp, a spokesman for the Center for Food Safety.

That's disturbing, he said, because genes from organisms that wouldn't normally breed could trigger toxins or allergens, in addition to desirable traits.

"You can put a fish and a strawberry in the same room together for a million years, and they're never going to cross breed," Culp said. "But if you put like species in a room together, they very well may share genetic material and create something that's different than either one of them."

The lead author of the paper said she doesn't believe a comparison can be drawn between the breeding practices of ancient Mexican farmers and what biotech companies do to develop genetically modified seeds.

"In the genes we looked at, early farmers did not 'change' anything within the gene," said Viviane Jaenicke, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "All (of the genes) were already present in the teosinte (corn's precursor) populations. All the early farmers did was to select teosinte plants which carried the alleles they were interested in. And this selection process created then the maize. So it is not 'engineering' but a selection process."

More exciting to Jaenicke is the fact that she and her colleagues were able to gather enough DNA from a 4,400-year-old ear of corn to study. They were surprised to find that genes found in modern-day corn were already present in the ancient corn.

"(That) means that 4,400 years ago, the ancient corn did not only look very much like modern corn, but probably also tasted very much like it," Jaenicke said. "I think it is amazing that so early in domestication, farmers had created a maize so close to the modern maize."

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