基于数字PCR的不同品种鸭组织中线粒体与核DNA拷贝数差异研究

肉和肉制品是人类生活的重要营养来源,但近年来肉制品中发生的掺假使假事件屡见不鲜,使得肉品的质量安全问题已经成为全世界关注的热点话题。以核酸为目标的动物源鉴定是当前普遍使用的方法。在核酸检测中,常用线粒体基因或核基因作为靶标,缺乏统一标准。以绍兴鸭和北京鸭等不同品种及生鲜组织(鸭血、鸭胸肉、鸭肝、鸭皮、鸭心和鸭腿肉)为实验材料,提取DNA后利用微滴式数字PCR开展线粒体和核DNA拷贝数的比较研究,以两者拷贝数及其比值的变异系数为判定依据。结果显示,核DNA的拷贝数在不同品种鸭组织间相对稳定,且变异系数小于线粒体DNA,表明核DNA是开展鸭肉制品掺假定量检测的最适DNA来源。鸭腿肉中线粒体/核DNA拷贝数比值的变异系数最小,表明线粒体DNA作为靶基因的鸭肉掺假比例定量检测时,鸭腿肉来源的肉制品是最佳选择。

Copy Number Variations of Mitochondrial DNA and Genomic DNA from Different Tissues of Duck Based on Digital PCR

Meat and meat products are the important nutrition sources for human being life,but adulteration of meat products occur frequently on the market in recent years,which makes the quality and safety of meat and meat products has become a hot topic all over the world.The identification of animal sources targeting nucleic acids is a widely used method at present.In nucleic acid detection,mitochondrial gene or nucleic genes are often used as targets,and there is a lack of unified standards.In this study,Shaoxing duck and Beijing duck and other different breeds and fresh tissues(duck blood,duck breast,duck liver,duck skin,duck heart and duck leg meat)were used as experimental materials,DNA was extracted from them and microdrop digital PCR was used to compare the copy numbers between mitochondrial DNA(mtDNA)and nucleic DNA.The variation coefficient of the copy number and their ratios were used as judgment basis.Results demonstrated that the copy number of nucleicDNA in various duck tissues were relatively stable,and the variation coefficient in nucleic DNA was smaller than that in mtDNA,suggesting that the nucleic DNA was the most suitable DNA source for the quantitative detection of adulteration of duck meat and products.Notably,the variation coefficient of the ratio of mtDNA copy number to nuclear DNA copy number in the duck leg meat was the smallest,indicating that duck leg meat was the best choice while we used mtDNA as the target gene for adulteration detection.