Assessing Copy Number of MON 810 Integrations in Commercial Seed Maize Varieties by 5′ Event-Specific Real-Time PCR Validated Method Coupled to $$2^{ - \Delta \Delta CT} $$ Analysis

Abstract

The objective of the present study was to assess the applicability of the MON 810 5′ event-specific method validated by the Community Reference Laboratory for Genetically Modified Food and Feed that is commonly used for quantitative purposes. This 5′ event-specific/hmg-taxon gene real-time polymerase chain reaction (PCR) protocol coupled to \(2^{ - \Delta \Delta CT} \) analysis was the chosen approach to determine the MON 810 insert copy number per haploid genome across 26 genetically modified commercial maize varieties. Variety DK 513 containing one copy integration per haploid genome was used as calibrator in each assay. Complementary data from end-point real-time PCRs that targeted specifically the MON 810 insert were also analyzed. Global results assessed and guaranteed the genetic intactness of the transgenic integration per haploid genome for 24 out of the 26 commercial varieties studied, which showed no significant differences between \(2^{ - \Delta \Delta CT} \) values respect to the calibrator value. Conversely, two varieties showed no intact transgenic insert in their genomes. This validated analytical method was suitable for MON 810 detection and quantification purposes.