Safety assessment of genetically engineered food: detection and monitoring of glyphosate-tolerant soybeans.

A detection technique for the genetically engineered food, glyphosate-tolerant soybean (GTS), was designed. Commercial soybeans imported from North America were cultured in pots and genomic DNA was isolated from their leaves. To detect the genes, promoter and terminator, involved in the expression of glyphosate tolerance, PCR was done using the genomic DNA and chemically synthesized primers specific to the genes. DNAs with predicted sizes were amplified and confirmed by DNA sequencing to be the genes responsible for the expression of glyphosate tolerance. Glyphosate-tolerant soybeans were found to form approximately 1.1% of the commercial soybeans, when commercially available soybeans were cultivated and number of soybeans resistant to glyphosate was found. This level is somewhat lower than an estimated value announced officially on the basis of the cultivation area of the glyphosate-tolerant soybeans.