Multi-laboratory validation of DNAxs including the statistical library DNAStatistX

Corina C G Benschop; Jerry Hoogenboom; Fiep Bargeman; Pauline Hovers; Martin Slagter; Jennifer van der Linden; Raymond Parag; Dennis Kruise; Katja Drobnic; Gregor Klucevsek; Walther Parson; Burkhard Berger; Francois Xavier Laurent; Magalie Faivre; Ayhan Ulus; Peter Schneider; Magdalena Bogus; Alexander L J Kneppers; Titia Sijen

doi:10.1016/j.fsigen.2020.102390

Multi-laboratory validation of DNAxs including the statistical library DNAStatistX

Forensic Sci Int Genet. 2020 Nov:49:102390. doi: 10.1016/j.fsigen.2020.102390. Epub 2020 Sep 7.

Authors

Corina C G Benschop¹, Jerry Hoogenboom², Fiep Bargeman³, Pauline Hovers⁴, Martin Slagter⁵, Jennifer van der Linden⁶, Raymond Parag⁷, Dennis Kruise⁸, Katja Drobnic⁹, Gregor Klucevsek¹⁰, Walther Parson¹¹, Burkhard Berger¹², Francois Xavier Laurent¹³, Magalie Faivre¹⁴, Ayhan Ulus¹⁵, Peter Schneider¹⁶, Magdalena Bogus¹⁷, Alexander L J Kneppers¹⁸, Titia Sijen¹⁹

Affiliations

¹ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
² Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
³ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
⁴ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
⁵ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
⁶ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
⁷ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
⁸ Netherlands Forensic Institute, Division of Digital and Biometric Traces, The Hague, The Netherlands. Electronic address: [email protected].
⁹ National forensic laboratory, Police, Ministry of the Interior, Ljubljana, Slovenia. Electronic address: [email protected].
¹⁰ National forensic laboratory, Police, Ministry of the Interior, Ljubljana, Slovenia. Electronic address: [email protected].
¹¹ Institute of Legal Medicine, Medical University of Innsbruck, Austria; Forensic Science Program, The Pennsylvania State University, University Park, PA, USA. Electronic address: [email protected].
¹² Institute of Legal Medicine, Medical University of Innsbruck, Austria. Electronic address: [email protected].
¹³ Institut National de Police Scientifique, Ecully, France. Electronic address: [email protected].
¹⁴ Institut National de Police Scientifique, Ecully, France. Electronic address: [email protected].
¹⁵ Institut National de Police Scientifique, Ecully, France. Electronic address: [email protected].
¹⁶ Institute of Legal Medicine, University Hospital of Cologne, Division of Forensic Molecular Genetics, Cologne, Germany. Electronic address: [email protected].
¹⁷ Institute of Legal Medicine, University Hospital of Cologne, Division of Forensic Molecular Genetics, Cologne, Germany. Electronic address: [email protected].
¹⁸ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].
¹⁹ Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497GB, The Hague, The Netherlands. Electronic address: [email protected].

PMID: 32937255
DOI: 10.1016/j.fsigen.2020.102390

Abstract

This study describes a multi-laboratory validation of DNAxs, a DNA eXpert System for the data management and probabilistic interpretation of DNA profiles [1], and its statistical library DNAStatistX to which, besides the organising laboratory, four laboratories participated. The software was modified to read multiple data formats and the study was performed prior to the release of the software to the forensic community. The first exercise explored all main functionalities of DNAxs with feedback on user-friendliness, installation and general performance. Next, every laboratory performed likelihood ratio (LR) calculations using their own dataset and a dataset provided by the organising laboratory. The organising laboratory performed LR calculations using all datasets. The datasets were generated with different STR typing kits or analysis systems and consisted of samples varying in DNA amounts, mixture ratios, number of contributors and drop-out level. Hypothesis sets had the correct, under- and over-assigned number of contributors and true and false donors as person of interest. When comparing the results between laboratories, the LRs were foremost within one unit on log10 scale. The few LR results that deviated more had differences for the parameters estimated by the optimizer within DNAStatistX. Some of these were indicated by failed iteration results, others by a failed model validation, since unrealistic hypotheses were included. When these results that do not meet the quality criteria were excluded, as is in accordance with interpretation guidelines, none of the analyses in the different laboratories yielded a different statement in the casework report. Nonetheless, changes in software parameters were sought that minimized differences in outcomes, which made the DNAStatistX module more robust. Overall, the software was found intuitive, user-friendly and valid for use in multiple laboratories.

Keywords: Continuous model; DNA profile interpretation; DNAStatistX; DNAxs; Likelihood ratio; Validation.

Publication types

Evaluation Study
Research Support, Non-U.S. Gov't
Validation Study

MeSH terms

DNA Fingerprinting*
Data Management
Humans
Laboratories*
Likelihood Functions*
Microsatellite Repeats
Software*
Statistics as Topic