The Development of a Series of Genomic DNA Reference Materials with Specific Copy Number Ratios for The Detection of Genetically Modified Maize DBN9936

• Published in: Foods 2024-02, Vol.13 (5), p.747
• Main Authors: Li, Jun, Gao, Hongfei, Li, Yunjing, Zhai, Shanshan, Xiao, Fang, Wu, Gang, Wu, Yuhua
• Format: Article
• Language: English
• Subjects: Biotechnology; Biotechnology industry; Calibration; certified reference material; Copy number; Corn; DBN9936; Deoxyribonucleic acid; Descriptive labeling; DNA; duplex droplet digital PCR; FDA approval; Food; Genetic modification; Genetically altered foods; Genetically engineered foods; Genetically modified crops; Genetically modified organisms; genomic DNA; Genomics; Homogeneity; Homozygotes; Industrial development; Inhomogeneity; Leaves; Market entry; Plant tissues; Plasmids; Property values; Quality control; Raw materials; Real estate; Reference materials; Safety and security measures; Seeds; Uncertainty
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods13050747

The genetically modified (GM) maize DBN9936 with a biosafety certificate will soon undergo commercial application. To monitor the safety of DBN9936 maize, three genomic DNA (gDNA) reference materials (RMs) (DBN9936a, DBN9936b, and DBN9936c) were prepared with nominal copy number ratios of 100%, 3%, and 1% for the DBN9936 event, respectively. DBN9936a was prepared from the leaf tissue gDNA of DBN9936 homozygotes, while DBN9936b and DBN9936c were prepared by the quantitative mixing of gDNA from the leaf tissues of DBN9936 homozygotes and non-GM counterparts. Validated DBN9936/ duplex droplet digital PCR was demonstrated to be an accurate reference method for conducting homogeneity study, stability study, and collaborative characterization. The minimum intake for one measurement was determined to be 2 μL, and the gDNA RMs were stable during transport at 37 °C for 14 days and storage at -20 °C for 18 months. Each gDNA RM was certified for three property values: DBN9936 event copy number concentration, reference gene copy number concentration, and DBN9936/ copy number ratio. The measurement uncertainty of the certified values took the uncertainty components related to possible inhomogeneity, instability, and characterization into account. This batch of gDNA RMs can be used for calibration and quality control when quantifying DBN9936 events.