Molecular characteristics including information of insertion site, flanking sequence, and copy numbers are the base for the safety assessment and subsequent monitoring of genetically modified organisms (GMOs), which has to be revealed thoroughly in a case-by-case manner. Although both polymerase chain reaction (PCR)-based and next-generation sequencing (NGS)-based approaches are proven to be effective in the molecular characterization of most of GM events, they often fail to work with GM maize events, mainly due to the genome complexity. In this study, by using NGS, we successfully identified the 3' end T-DNA insertion site and flanking sequence of a GM maize event IE09S034, which were confirmed by PCR amplification and Sanger sequencing. Notably, insertions of unintended exogenous elements were revealed in this event although the single copy of target exogenous genes was also confirmed by digital PCR. The output of this study provides novel and important genetic evidence for the safety assessment and monitoring of GM maize event IE09S034.

中文翻译：

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使用下一代测序技术鉴定转基因玉米事件IE09S034的T-DNA插入位点和侧翼序列。

分子特征，包括插入位点，侧翼序列和拷贝数信息，是安全评估和随后监测转基因生物（GMO）的基础，必须逐案彻底揭露。尽管基于聚合酶链反应（PCR）的方法和基于下一代测序（NGS）的方法均已被证明可有效地对大多数转基因事件进行分子鉴定，但它们通常无法处理转基因玉米事件，主要原因是基因组复杂性。在这项研究中，通过使用NGS，我们成功鉴定了转基因玉米事件IE09S034的3'端T-DNA插入位点和侧翼序列，已通过PCR扩增和Sanger测序证实。值得注意的是 尽管通过数字PCR也证实了目标外源基因的单拷贝，但在该事件中发现了意外外源元件的插入。这项研究的结果为转基因玉米事件IE09S034的安全性评估和监测提供了新颖而重要的遗传证据。