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Euroforgen-NoE Collaborative Exercise on LRmix to Demonstrate Standardization of the Interpretation of Complex DNA Profiles

NCJ Number
Forensic Science International: Genetics Volume: 9 Dated: March 2014 Pages: 47-54
L. Prieto; H. Haned; A. Mosquera; M. Crespillo; M. Aleman; M. Aler; F. Alvarez; C. Baeza-Richer; A. Dominguez; C. Doutremepuich; M.J. Farfan; M. Fenger-Gron; J.M. Garcia-Ganivet; E. Gonzalez-Moya; L. Hombreiro; M.V. Lareu; B. Martinez-Jarreta; S. Merigioli; P. Milans del Bosch; N. Morling; M. Munoz-Nieto; E. Ortego-Gonzalez; S. Pedrosa; R. Perez; C. Solis; I. Yurrebaso; P. Gill
Date Published
March 2014
8 pages
The European Forensic Genetics Network of Excellence (Euroforgen-NoE) collaborative developed a training course that uses the LRmix program in calculating complex DNA profiles in mixtures, so as to standardize such calculations among laboratories.
The project demonstrates that the standardization of procedures for analyzing complex DNA profiles can be achieved provided the same sets of hypotheses are compared based on suitable tools and uniform training for DNA forensic experts. The Euroforgen-NoE training program for DNA experts was clearly instrumental in facilitating collaboration among the 18 participating laboratories regarding the analysis of complex DNA profiles. The software used in this collaborative training was LRmix. This open-source solution enables the calculation of likelihood ratios (LRs) of complex DNA mixtures, taking into account the twin effects of drop-out and drop-in. In addition, several PCR replicates from the same DNA extract can be analyzed simultaneously. This feature reduces the subjectivity involved with deriving a consensus profile and avoids the associated problems. This has the advantage of incorporating all available information into a single LR calculation. In the training exercise, the same initial LR was obtained from all participants, since all participants derived and tested the same hypotheses and used the same initial parameters. A table summarizes the calculated results. The procedure used to analyze DNA profiles using the LRmix package is explained in tutorials available from Forensim's Web site at http://forensim.r-forge.r-project.org/, and the process is also described in detail by Gill et al., 2013. 3 tables, 1 figure, and 19 references