转基因玉米品系GA21拷贝数百分含量与质量百分含量关系研究

Study on the relationship between the copy number percentage and mass percentage in transgenic maize event GA21

转基因成分含量一般以质量百分含量表示,而转基因成分定量检测只能检测内、外源基因的拷贝数,并以外源和内源基因拷贝数百分比值表示其含量。由于玉米、大米等种子含有三倍体的胚乳,导致样品中转基因成分质量百分含量并不等于其拷贝数百分比值。为深入探究两者之间的关系,本文首先建立了转基因玉米品系GA21二重数字PCR检测方法,并在此基础上,测定了品系GA21 5种不同质量百分含量标准参考物质的外源和内源基因拷贝数百分比。结果表明,该品系不同质量百分含量与其拷贝数百分比值存在线性相关,线性方程为:y=0.2464x+0.1458,两者相关系数达0.9951。本研究提供了一种可将样品拷贝数百分比值直接转化为质量百分含量的新方法,该方法适用于玉米、大米等含胚乳种子及其产品转基因质量百分含量的检测。

The content of genetically modified （GM） ingredients is generally labeled in mass fraction, while the quantitative detection methods like real-time PCR or digital PCR can only determine the copy numbers of the endogenous and exogenous gene,and the content of GM ingredients are expressed in copy number ratio. Due to the existence of endosperm triploid （3n） in seeds like corn and rice etc.,GM mass percentage is not equal to the value of copy number percentage. In order to study the relationship between of them,we established a duplex digital PCR method for GM event GA21 ,and on this basis,determined the GA21/HMG copy number percentage of five certified reference materials with different mass percentage. Result shows that there is a linear correlation between them,the linear equation is：y=02464x＋0.1458, with a 0.9951 higher correlation coefficient. This study provides a new way for the direct conversion of copy number percentage to the mass percentage,and it is suitable for the mass fraction determination of GM ingredient in seeds and derived product like corn and rice etc. that contains endosperms.