BACKGROUND Compared with the traditional qualitative polymerase chain reaction (PCR), which only identifies the category of species, the quantitative PCR method provides a value, which is very important for appropriate penalty enforcement according to the extent of adulteration. However, most of the currently quantitative PCR methods were based on mitochondrial genes, expressing different copy numbers in different cells and reducing the accuracy of quantitative results. In this study, the single-copy nuclear housekeeping genes, instead of multicopy mitochondrial genes, were selected as both the camel species-specific and the reference genes to develop a novel normalized PCR system. RESULTS This system had an excellent linear correlation (R2 = 0.9614) between the camel milk content and the Ct ratio (specific/reference genes), and allowed quantitative detecting percent content of camel milk in adulterated milk samples. The accuracy was effectively validated by simulated adulterated samples with the recoveries ranging from 90% to 120% and CV values <10%, exhibiting sufficient parameters of trueness and precision. CONCLUSION The normalized PCR system based on single-copy nuclear genes was a simple, rapid, and reliable method for the determination of percent content of camel milk in adulterated milk samples, and also provided a technical support for appropriate penalty enforcement. This article is protected by copyright. All rights reserved.

中文翻译：

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基于单拷贝核基因的标准化实时PCR系统测定掺假牛奶样品中骆驼奶的百分比含量

背景技术与传统的定性聚合酶链反应（PCR）方法相比，该方法只能识别物种的类别，定量PCR方法提供了一个价值，这对于根据掺假的程度进行适当的处​​罚是非常重要的。然而，目前大多数定量PCR方法都是基于线粒体基因，在不同细胞中表达不同的拷贝数，降低了定量结果的准确性。在这项研究中，单拷贝核管家基因，而不是多拷贝线粒体基因，被选为骆驼物种特异性基因和参考基因，以开发新的标准化 PCR 系统。结果 该系统在骆驼奶含量和 Ct 比（特定/参考基因）之间具有极好的线性相关性 (R2 = 0.9614)，并允许定量检测掺假牛奶样品中骆驼奶的百分比含量。通过模拟掺假样品有效验证了准确度，回收率范围为 90% 至 120%，CV 值 <10%，显示出足够的真实性和精密度参数。结论基于单拷贝核基因的归一化PCR系统是一种简单、快速、可靠的方法，用于测定掺假牛奶样品中骆驼奶的百分比含量，也为适当的处罚提供了技术支持。本文受版权保护。版权所有。表现出足够的真实性和精确度参数。结论基于单拷贝核基因的归一化PCR系统是一种简单、快速、可靠的方法，用于测定掺假牛奶样品中骆驼奶的百分比含量，也为适当的处罚提供了技术支持。本文受版权保护。版权所有。表现出足够的真实性和精确度参数。结论基于单拷贝核基因的归一化PCR系统是一种简单、快速、可靠的方法，用于测定掺假牛奶样品中骆驼奶的百分比含量，也为适当的处罚提供了技术支持。本文受版权保护。版权所有。