Gill Peter, Haned Hinda, Bleka Oyvind, Hansson Oskar, Dørum Guro, Egeland Thore
Norwegian Institute of Public Health, Department of Forensic Biology, PO Box 4404 Nydalen, 0403 Oslo, Norway; Department of Forensic Medicine, Sognsvannsveien 20, Rikshospitalet, 0372 Oslo, Norway.
Netherlands Forensic Institute, Department of Human Biological Traces, The Hague, The Netherlands.
Forensic Sci Int Genet. 2015 Sep;18:100-17. doi: 10.1016/j.fsigen.2015.03.014. Epub 2015 Mar 27.
The introduction of Short Tandem Repeat (STR) DNA was a revolution within a revolution that transformed forensic DNA profiling into a tool that could be used, for the first time, to create National DNA databases. This transformation would not have been possible without the concurrent development of fluorescent automated sequencers, combined with the ability to multiplex several loci together. Use of the polymerase chain reaction (PCR) increased the sensitivity of the method to enable the analysis of a handful of cells. The first multiplexes were simple: 'the quad', introduced by the defunct UK Forensic Science Service (FSS) in 1994, rapidly followed by a more discriminating 'six-plex' (Second Generation Multiplex) in 1995 that was used to create the world's first national DNA database. The success of the database rapidly outgrew the functionality of the original system - by the year 2000 a new multiplex of ten-loci was introduced to reduce the chance of adventitious matches. The technology was adopted world-wide, albeit with different loci. The political requirement to introduce pan-European databases encouraged standardisation - the development of European Standard Set (ESS) of markers comprising twelve-loci is the latest iteration. Although development has been impressive, the methods used to interpret evidence have lagged behind. For example, the theory to interpret complex DNA profiles (low-level mixtures), had been developed fifteen years ago, but only in the past year or so, are the concepts starting to be widely adopted. A plethora of different models (some commercial and others non-commercial) have appeared. This has led to a confusing 'debate' about the 'best' to use. The different models available are described along with their advantages and disadvantages. A section discusses the development of national DNA databases, along with details of an associated controversy to estimate the strength of evidence of matches. Current methodology is limited to searches of complete profiles - another example where the interpretation of matches has not kept pace with development of theory. STRs have also transformed the area of Disaster Victim Identification (DVI) which frequently requires kinship analysis. However, genotyping efficiency is complicated by complex, degraded DNA profiles. Finally, there is now a detailed understanding of the causes of stochastic effects that cause DNA profiles to exhibit the phenomena of drop-out and drop-in, along with artefacts such as stutters. The phenomena discussed include: heterozygote balance; stutter; degradation; the effect of decreasing quantities of DNA; the dilution effect.
短串联重复序列（STR）DNA的引入是一场“革命中的革命”，它将法医DNA分析技术转变为一种首次可用于创建国家DNA数据库的工具。如果没有荧光自动测序仪的同步发展以及将多个基因座一起进行多重分析的能力，这种转变是不可能实现的。聚合酶链反应（PCR）的应用提高了该方法的灵敏度，能够对少量细胞进行分析。最初的多重分析很简单：1994年已不复存在的英国法医科学服务局（FSS）推出了“四基因座组合”，随后在1995年迅速出现了更具区分性的“六基因座组合”（第二代多重分析），并被用于创建世界上第一个国家DNA数据库。该数据库的成功很快超出了原始系统的功能——到2000年，引入了一种新的十基因座多重分析方法，以减少偶然匹配的几率。这项技术在全球范围内得到采用，尽管使用的基因座有所不同。引入泛欧数据库的政治需求推动了标准化——包含十二个基因座的欧洲标准标记集（ESS）的开发是最新进展。尽管发展令人印象深刻，但用于解释证据的方法却滞后了。例如，解释复杂DNA图谱（低水平混合图谱）的理论早在十五年前就已提出，但直到过去一年左右，这些概念才开始被广泛采用。出现了大量不同的模型（有些是商业模型，有些是非商业模型）。这引发了一场关于使用“最佳”模型的令人困惑的“争论”。文中描述了现有不同模型及其优缺点。有一节讨论了国家DNA数据库的发展情况，以及与之相关的一场争议的细节，这场争议涉及如何评估匹配证据的强度。当前的方法仅限于对完整图谱进行搜索——这是另一个匹配解释未能跟上理论发展步伐的例子。STRs还改变了灾难受害者身份识别（DVI）领域，该领域经常需要进行亲缘关系分析。然而，复杂、降解的DNA图谱使基因分型效率变得复杂。最后，现在对导致DNA图谱出现缺失和插入现象以及诸如拖尾等假象的随机效应的原因有了详细了解。讨论的现象包括：杂合子平衡；拖尾；降解；DNA数量减少的影响；稀释效应。
