The detection of genetically modified organisms in feedstuffs using PCR methods rely on the yield and quality of the extracted genomic plant DNA. The used extraction methods must be able to provide DNA of sufficient amounts of non-fragmented DNA that is free of PCR inhibitors. This article describes the comparison of methods for the extraction of DNA from maize gluten as an example for a protein-rich corn-based feedstuff sample and the following validation of two selected methods. These selected methods are based on lysis by a cetyltrimethylammonium bromide buffer followed by precipitation of genomic DNA and on a kit-based procedure. To calculate the amount of amplifiable DNA copies and the PCR efficiency in the extracts, the crossing points of the real-time PCR curves were used. The comparison of different extraction methods showed that the two selected methods yielded the highest amounts of amplifiable DNA based on the amplification of the maize specific reference gene hmg by real-time TaqMan PCR. Additionally, approaches to increase DNA yield or concentration by variation of the protocol are discussed. Both validation studies were conducted by the working group “PCR analytics in feed” of the Association of German Agricultural and Research Institutes.

使用PCR方法检测饲料中的转基因生物取决于提取的基因组植物DNA的产量和质量。所使用的提取方法必须能够提供足够数量的不含PCR抑制剂的非片段化DNA。本文介绍了从玉米麸质中提取DNA的方法的比较，以富含蛋白质的玉米饲料样品为例，并对以下两种选定方法进行了验证。这些选择的方法基于十六烷基三甲基溴化铵缓冲液的裂解，然后沉淀基因组DNA和基于试剂盒的方法。为了计算提取物中可扩增DNA拷贝的数量和PCR效率，使用了实时PCR曲线的交叉点。通过实时TaqMan PCR进行hmg。另外，讨论了通过改变方案来增加DNA产量或浓度的方法。两项验证研究均由德国农业和研究所协会“饲料中的PCR分析”工作组进行。