Friday, May 6, 2011
EPA Proposal Would Exempt Some GMOs From Registry
By Sara Reardon
May 6, 2011
Many forest ecologists dream of restoring the once-great American chestnut tree to the Appalachian range. For decades, researchers have been trying to transfer the natural blight-resistance genes of the closely related Chinese chestnut by crossbreeding the two trees, with varying degrees of success. If the Chinese chestnut’s resistance genes were known—and forest geneticist Charles Maynard at the State University of New York (SUNY) in Syracuse says his group is close to identifying a few—using existing transgenic techniques to transfer them directly into the American variety would be a welcome shortcut.
But this high-tech solution would come with considerable drawbacks. Even though the new and improved chestnut would not contain any DNA that it couldn’t have acquired naturally through conventional breeding, its chestnuts would be considered a transgenic crop. That means anyone who wanted to plant it outside would have to jump through costly and time-consuming hoops to satisfy regulatory agencies’ concerns about safety.
The time is ripe, some researchers are arguing, for a distinction here. They propose that plants dubbed “cisgenic,” that is, containing only genetic material from sexually compatible species, be exempted from the scrutiny and safety tests that agencies currently demand for transgenic plants on a case-by-case basis. In March, the U.S. Environmental Protection Agency opened a request for comments on a draft rule that would exempt cisgenic organisms from the requirement to be registered with EPA before being field-tested or marketed. The comment period closed 15 April.
Opinions in the comments ran hot, echoing a 2006 controversy in which Dutch researchers proposed regulatory exemption in Europe for cisgenic plants in the journal EMBO reports. There is nothing intrinsically dangerous about such plants, the authors argued, despite their provenance in a biotech lab. They and other proponents of this new classification, like forest biotechnologist Steven Strauss of Oregon State University, Corvallis, point out that during traditional breeding, plants swap huge chunks of DNA, and a breeder doesn’t know what other genes might be transferred along with the gene of interest. Similarly, classical mutagenesis methods, which involve treating pollen with radiation or chemicals and then screening for desirable mutants, are unregulated. By contrast, moving a specific gene or gene using biotech methods—say, injecting the new DNA directly into plants’ germ cells—would let researchers track precisely what is being transferred. There’s no scientific reason to think moving just one piece of DNA might be a problem, says biologist Wayne Parrott of the University of Georgia in Athens, “but if you chop a chromosome up by blasting a cell with radiation, that’s not going to be a problem.”
But the proposal has angered scientists on both sides of the broader debate about genetically modified organisms (GMOs). Cell biologist David Schubert of the Salk Institute for Biological Studies in San Diego, California, who believes that GMOs deserve more regulation, calls cisgenics “semantics and illusions to scam the public into thinking they are eating a ‘natural’ product.”
Some biotech allies who would like to see less regulation of GM crops scorn the idea for different reasons. Giving cisgenics special treatment would unfairly impugn the safety of transgenics, says population geneticist and independent biotech consultant L. Val Giddings, adding that the process by which DNA is manipulated in a plant tells one nothing about the potential hazard of the resulting product.
SUNY molecular biologist William Powell, who works with Maynard on the American Chestnut Research and Restoration Project, said in an e-mail that he thinks EPA’s proposed rule is “a step in the right direction.” But he cautions that a host of technical issues must be resolved before cisgenic plants would be ready for prime time. No cisgenic plants have yet been presented for EPA scrutiny.
At the University of California, Davis, plant biologist Charles Gasser is working on another genetic modification approach that may also be considered under EPA’s proposed rule: improving plants by tweaking their own genes instead of introducing foreign genes. Strauss calls such an approach “intragenic.” In a March paper in the Proceedings of the National Academy of Sciences, Gasser and colleagues described a gene called INO that, when disrupted in natural mutants, causes Spanish sugar apples to be seedless. INO is the first known gene for seeds and is likely present in popular fruits such as regular apples and avocados, Gasser says. In addition to conventional crossing experiments, his group is testing whether gene targeting approaches could be used to delete the gene in these other fruits, leaving no foreign DNA behind.
Getting any cisgenic or intragenic crop to market would require their approval by the U.S. Department of Agriculture (USDA): EPA steps in only if a GM plant has genes that act as pesticides. Researchers would likely want approval from the Food and Drug Administration (FDA) as well to lessen their susceptibility to lawsuits. Strauss says EPA tends to be the strictest regulator: If EPA exempts cisgenics from registration, USDA and FDA may follow suit. But the legal issues will take some work. Freeing such plants from registration would complicate USDA’s job when exporting them to countries with GM labeling laws. The next step is for EPA to present a final proposed rule for entry in the Federal Register.