Gaines Michelle L, Wojtkiewicz Patrick W, Valentine Jennifer A, Brown Connie L
North Louisiana Criminalistics Laboratory, Shreveport 71101, USA.
J Forensic Sci. 2002 Nov;47(6):1224-37.
The forensic community continues to seek improvements in DNA typing methods on aspects such as sensitivity and efficacy. Reducing the volume of the AmpFlSTR Profiler Plus reagents offered greater sensitivity and improved the chance of obtaining useful results for samples with very low quantities of DNA and multiple source samples. On the downside, amplifications initiated with less than 0.4 ng of DNA exhibited a twofold increase in the standard deviation of peak ratios. This research suggested a twofold approach to analyzing samples. For samples with greater than 0.25 ng of DNA, a 25 microL reaction is appropriate. Samples that did not demonstrate quantifiable results, or that have less than 0.25 ng, can be amplified by drying the sample directly in the PCR tube and amplifying in a 5 microL reaction. The analyst can expect at least limited results with as little as 0.03 ng of DNA in the 5 microL reaction.
法医界一直在寻求改进DNA分型方法，如提高灵敏度和效率。减少AmpFlSTR Profiler Plus试剂的用量可提高灵敏度，并增加从极少量DNA样本和多源样本中获得有用结果的机会。不利的是，起始DNA量少于0.4 ng时，峰高比值的标准偏差会增加两倍。该研究提出了一种双重分析样本的方法。对于DNA量大于0.25 ng的样本，25 μL反应体系合适。未得到可量化结果或DNA量少于0.25 ng的样本，可直接在PCR管中干燥样本并在5 μL反应体系中进行扩增。分析人员可以预期，在5 μL反应体系中，即使只有0.03 ng的DNA也至少能得到有限的结果。
