Mulero Julio J, Chang Chien Wei, Hennessy Lori K
Human Identification Group, Applied Biosystems M/S 404-3, 850 Lincoln Centre Drive, Foster City, CA 94404, USA.
J Forensic Sci. 2006 Sep;51(5):1069-73. doi: 10.1111/j.1556-4029.2006.00227.x.
Stutter products generated during DNA amplification by the polymerase chain reaction (PCR) may complicate mixture interpretation. The PCR amplification of the DYS392 locus typically results in three distinct detectable PCR products: the true allele product (N), a stutter product three bases smaller (N-3), and a reproducible low-level product, three bases larger (N+3). Sequence analysis of the N+3 product demonstrated that its sequence is one TAT repeat longer than the true allele product. Our experiments demonstrated that the quantity of both N-3 and N+3 stutter increased as the allele number increased. The percent stutter also increased as the magnesium concentration was increased in the reaction, as well as when the amount of input DNA was decreased. As both stutter products behave in a similar and reproducible fashion, the same rules that apply to the interpretation of N-3 stutter products in short tandem repeat analysis, can be applied to N+3 stutters. The characterization of the DYS392 N+3 product is the first detailed published study of a stutter product larger than the true allele.
聚合酶链反应（PCR）进行DNA扩增时产生的拖尾产物可能会使混合物分析变得复杂。DYS392基因座的PCR扩增通常会产生三种不同的可检测PCR产物：真实等位基因产物（N）、比其小三个碱基的拖尾产物（N-3）以及可重复出现的低水平产物，比其大三个碱基（N+3）。对N+3产物的序列分析表明，其序列比真实等位基因产物多一个TAT重复序列。我们的实验表明，随着等位基因数量的增加，N-3和N+3拖尾产物的数量都会增加。随着反应中镁离子浓度的增加以及输入DNA量的减少，拖尾百分比也会增加。由于这两种拖尾产物的行为方式相似且具有可重复性，因此适用于短串联重复序列分析中N-3拖尾产物解释的相同规则，也可应用于N+3拖尾。对DYS392 N+3产物的表征是首次发表的关于比真实等位基因大的拖尾产物的详细研究。
