Gómez J, Carracedo A
Quality Control Unit (Unidad de Garantía de Calidad), National Institute of Toxicology, Ministry of Justice, C/Luis Cabrera 9, 28002 Madrid, Spain.
Forensic Sci Int. 2000 Oct 9;114(1):21-30. doi: 10.1016/s0379-0738(00)00288-7.
A total of 28 laboratories (labs) submitted results for the 1998 collaborative exercise and the proficiency testing program of the Spanish and Portuguese Working Group of the International Society for Forensic Genetics (GEP-ISFG) group. This number increased to 46 labs in 1999. Six bloodstains were submitted, each one with 200 microl soaked in cotton except the sample no. 6 submitted for DNA quantification which had 2 microl. One of the samples was a mixed stain. A paternity testing case and a criminal case in the 1998 trial (GEP'98) and two paternity testing cases in 1999 (GEP'99) were included and the statistical evaluation of the evidence was requested in both cases. In the GEP'99 trial, a theoretical paternity testing case was included. A total of 52 DNA genetic markers were used by the participants in the GEP'98 trial, which increased to 101 in GEP'99. Despite this increasing number of participating labs, results remained quite satisfactory. All the labs used PCR-based DNA polymorphisms with an increasing number of markers, obtaining good results. SLPs were used by a decreasing number of labs but the results indicated a good level of expertise despite the different protocols used. Good results were also obtained for mtDNA despite the difficulties presented by the samples due to the presence of length heteroplasmy in some samples in both trials. The detection of heteroplasmy should, however, be improved. Similar conclusions were reached for both, the paternity and the criminal case by all the labs. Common methodologies for the statistical evaluation of the paternity case were used and the paternity index and the probability of paternity (with an a priori value of 0.5) reported by most of the labs. Also, a great uniformity was found in the evaluation of the criminal case despite the lack of a specific hypothesis in the design of the exercise. Some errors in statistical programs or in calculations were detected in a theoretical paternity case included in the GEP'99 trial for statistical analysis.
共有28个实验室提交了1998年国际法医遗传学协会（GEP - ISFG）西班牙和葡萄牙工作组协作实验及能力验证计划的结果。1999年，这一数字增至46个实验室。提交了6份血迹样本，除用于DNA定量的6号样本为2微升外，每份样本均有200微升浸泡在棉花中。其中一个样本为混合污渍。1998年试验（GEP'98）包含一个亲子鉴定案例和一个刑事案件，1999年（GEP'99）包含两个亲子鉴定案例，两个案例均要求对证据进行统计评估。在GEP'99试验中，还纳入了一个理论亲子鉴定案例。GEP'98试验的参与者共使用了52个DNA遗传标记，在GEP'99中增至101个。尽管参与实验室数量不断增加，但结果仍相当令人满意。所有实验室都使用基于PCR的DNA多态性技术，标记数量不断增加，取得了良好结果。使用序列长度多态性（SLP）的实验室数量在减少，但尽管使用的方案不同，结果显示专业水平良好。尽管在两次试验中，部分样本因存在长度异质性而给样本分析带来困难，但线粒体DNA（mtDNA）检测仍取得了良好结果。不过，异质性的检测仍需改进。所有实验室在亲子鉴定和刑事案件中均得出了类似结论。大多数实验室采用了亲子鉴定案例统计评估的常用方法，并报告了亲权指数和父权概率（先验值为0.5）。此外，尽管在实验设计中缺乏具体假设，但在刑事案件评估中仍发现了很大的一致性。在GEP'99试验纳入的用于统计分析的一个理论亲子鉴定案例中，检测到了统计程序或计算中的一些错误。
