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GMO crop or non-GMO? Exorcist gene offers both

Ha! And you thought “Exorcist” was only a horror movie. But now comes what has to be one of the weirdest developments in the ongoing brouhaha over genetically engineered crops.

Perhaps it's a sequel to the fuss that occurred a year or so over the so-called “Terminator” gene, the technology that would render seed from a genetically modified crop unusable for planting a subsequent crop and thus allow the seed company to protect its intellectual property.

Or maybe someone's just got a thing for incorporating movie names into the GMO fray (the Exorcist gene is also being called “Terminator II”).

At any rate, the hullabaloo about using genetically modified crops in foods, particularly in Europe, has led to the Exorcist technology. When I first read about it, I thought it an insider joke among researchers, but it comes from two reputable scientists working with a California biotech firm, and has been detailed in the journal Nature Biotechnology.

There's a very complex explanation, but the bottom line is that Exorcist uses a protein called Cre that acts as “molecular scissors” to snip out any DNA that lies between two particular DNA markers, called IoxP.

It works this way: When the biotech wizards introduce a foreign gene into a plant — such as for herbicide resistance — they could also include genes for Cre and IoxP.

A farmer would plant the seed as for a genetically modified crop. But if for some reason he later felt the crop would be more marketable without the GM component, the foreign gene could be erased by triggering the Cre/IoxP mechanism. This could take place at an early stage of fruit development or before pollen started to ripen. The scientists say, further, the process could be expanded to even wipe out all traces of the Exorcist gene itself. Now you see it, now you don't.

Ta-daa, the best of both worlds: Farmers would get the advantages of GM crops, while ever so picky consumers would get a product with no foreign DNA.

In theory, at least, that's how it would work. Experts are already lining up to debate whether the technology will work under widely varying field growing conditions, both here and in other countries. And a USDA scientist, who's also been working with Cre/IoxP, contends that the snipped foreign genes aren't really eliminated by the Exorcist system, but rather remain in the plant cells in a form he hasn't yet been able to figure out.

Whether the Exorcist technology can be made consistently workable remains to be seen, but it's development shows just how wide-ranging are the possibilities in the world of genetic engineering.

The major question facing the future of genetically modified crops, however, likely won't be whether or not scientists can continue expanding their ability to alter Nature, but whether the end product will be accepted by an increasingly fickle consumer, who may not know where milk comes from but agonizes about the possible harmful effects of “Frankenfoods” on her/his family.

e-mail: [email protected].

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