Cal Poly students in an advanced weed science course validated Monsanto's claim that genes from genetically modified Roundup Readyâ corn did not "jump" to a biotype of ryegrass from a Chico-area orchard, as biotechnology critics argued could happen.

Critics claim the primary danger is that herbicide-resistant genes could jump from genetically modified crops to other wild or domesticated species, producing "super weeds" that would resist conventional control methods. Monsanto maintains it would be very difficult, if not impossible, for a weed to mutate under normal circumstances due to the genetics involved.

Under the direction of Crop Science Professor Scott J. Steinmaus, students conducted a crops lab experiment of genetically modified cotton, a resistant and Roundup-Ready-variety of corn, and one resistant and one susceptible biotype of ryegrass (Chico and San Luis, respectively). Of these test plants, only the Chico strain of ryegrass, Roundup Ready corn and cotton survived the pesticide application at the highest legal rate.

Students next set about isolating DNA from both genetically modified organisms and the nongenetically modified organisms (NGMO). Each student worked at independent lab stations to separate the DNA from other cellular contents.

According to Steinmaus, "Each student was 'hands-on' in the lab, they weren't just watching. They all had the opportunity to isolate the DNA, amplify the specific modified gene through the use of the polymerase chain reaction (PCR), and inject the PCR products into an electrically charged gel pad.

When dye was added to the gel pad, the location of the gene could be seen under ultraviolet light," Steinmaus said. "We found Monsanto's altered gene in the genetically modified organisms crops. We didn't find it in any of the other species including the resistant Chico ryegrass.

"Resistant ryegrass from Chico does not have the same altered gene as the genetically modified organisms in Roundup Ready crops," Steinmaus explained. "Therefore, the altered gene could not have jumped -- or transferred -- from the crop to the weed. The next step will be to determine why the weed is resistant."

Steinmaus' study and the class project that investigated herbicide resistance in weeds was funded by an Agriculture Education Foundation grant.