title: A single nucleotide polymorphism (SNP839) in the adh1 reference gene affects the quantitation of genetically modified maize (Zea mays L.).
abstract: The real-time PCR methods recommended in the European Union for the quantitation of genetically modified (GM) maize events NK603, GA21, and MON 863 measure the number of copies of the GM event in relation to those of the maize-specific adh1 reference gene. The study reported here revealed that the targeted 70 base pair adh1 region exhibits a single nucleotide polymorphism (SNP839) that hampers the binding of the reverse primer used in the adh1 detection method. Partial fragments of the adh1-A and adh1-F allele were cloned. By allele-specific real-time PCR, it was shown that SNP839 corresponds to a common allelic polymorphism in maize. As a result, the quantitation of the GM maize events mentioned is positively or negatively biased, depending on the adh1 genotype of sample and calibrant. Therefore, it is proposed to revise the quantitative detection methods for NK603, GA21, and MON 863 maize.
authors.affiliation: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Broothaerts
authors.forename: Philippe
authors.initials: P
authors.lastname: Corbisier
authors.forename: Heinz
authors.initials: H
authors.lastname: Schimmel
authors.forename: Stefanie
authors.initials: S
authors.lastname: Trapmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Vincent
authors.forename: Hendrik
authors.initials: H
authors.lastname: Emons