A method of detecting recombinant DNAs from four lines of genetically modified maize.

A method using polymerase chain reaction (PCR) was designed for the detection of genetically modified maize (GM-maize). There are four lines of GM-maize imported from the United States, and the presence of recombinant deoxyribonucleic acid (DNA) in the maize could be detected with four pairs of specific oligonucleotide primers designed from the sequences of the newly introduced genes. The maize zein gene was also detected as an internal control. This method allows specific detection of each of Bt11, Event176, MON810 and LIBERTY by using pairs of specific primers designed to amplify a segment including part of the exogenously introduced sequence and part of the intrinsic maize sequence. The detection sensitivity was about 0.05% for Event176, MON810 and LIBERTY, and about 0.01% for Bt11. To distinguish among three insect-resistant GM-maize lines, we designed a multiplex PCR method. These three GM-maize lines were distinguishable on the basis of the expected lengths of their amplicons.