The DNA eXpert System, DNAxs, aids in the data management and efficient, with low risk for error, interpretation and comparison of DNA profiling data. This study describes how the expert system was realized and how it evolved during the first three years after the initial implementation.

Insight is given in the software architecture, its modular design enabling to communicate with various software systems and how this system was implemented in a casework setting. The importance of quality aspects are highlighted, such as (automated) software testing at various levels. The code coverage is presented as well as the numbers of software bugs that were discovered. The usefulness of the overall software suite and automated steps in DNA profile interpretation were evaluated based on its usage in forensic DNA at the developing laboratory. Because of automated profile comparisons, cases with larger numbers of profiles can be handled, are less prone to error and less time consuming.

The implementation of DNAStatistX into DNAxs enabled a more efficient workflow. Extensive automated software tests and an audit trail serve as quality aspects for the usage of DNAxs. In times of the pandemic this software was found even more valuable than ever thought as it enabled working from home and it proved robust when used with many simultaneous users. The DNAxs software is regarded future proof and many new features and applications are envisioned.

Further information can be found under the tab: ''Publications DNAxs''

DNAxs and DNAStatistX were used in a multi-laboratory validation study in which four laboratories participated. I.e. the Netherlands Forensic Institute in the Netherlands, Institute of Legal Medicine in Austria, National Forensic Laboratory in Slovenia, Institute of Legal Medicine (Cologne) in Germany, and Institut National de Police Scientifique (Ecully) in France. The study was partly funded by the European Union’s Internal Security Fund - Police (Proposal Number: 820838, Proposal Acronym: DNAxs2.0).

In this study, the software was modified to read multiple data formats. First, participants performed an exercise to explore all main functionalities of DNAxs and gave 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 organizing laboratory (NFI). The organizing 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 the pre-set range of variation. 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. The dataset of the organizing laboratory is provided to aid the implementation of the DNAxs/DNAStatistX software within other laboratories.

With the development of NFI xs suite software, no further development is performed on two open-source software applications, developed by the NFI.

The semi-continuous model LRmix Studio, the expert system dedicated to the interpretation of forensic DNA profiles, and SmartRank, dedicated to searching national DNA databases with complex DNA profiles, are replaced by more advanced systems like DNAxs, DatabankXS and DNAStatistX (including ProbRank).

Both LRmix Studio and SmartRank are no longer available from lrmixstudio.org, but have been migrated to GitHub from from where the software can be downloaded

For any information on the DNAxs suite software read the information above and/or send an email to dnaxs@nfi.nl

• C.C.G. Benschop, J. Hoogenboom, P. Hovers, M. Slagter, D. Kruise, R. Parag, K. Steensma, K. Slooten, J.H.A. Nagel, P. Dieltjes, V. van Marion, H. van Paassen, J. de Jong, C. Creeten, T. Sijen, A.L.J. Kneppers. DNAxs/DNAStatistX: Development and validation of a software suite for the data management and probabilistic interpretation of DNA profiles. Forensic Sci. Int. Genet. 42 (2019) 81-89.
   
• C.C.G. Benschop, J. van der Linden, J. Hoogenboom, R. Ypma, H. Haned. Automated estimation of the number of contributors in autosomal short tandem repeat profiles using a machine learning approach. Forensic Sci. Int. Genet. 43 (2019) 102150.
   
•  C.C.G. Benschop, A. Nijveld, F.E. Duijs, T. Sijen, An assessment of the performance of the probabilistic genotyping software EuroForMix: trends in likelihood ratios and analysis of Type I & II errors, Forensic Sci. Int. Genet. 42 (2019) 31–38.
  Download de PowerPlex Fusion 6C 2p-5p mixtures dataset die gebruikt is in deze studie.
   
• M. Slagter, D. Kruise, L. van Ommen, J. Hoogenboom, K. Steensma, J. de Jong, P. Hovers, R. Parag, J. van der Linden, A.L.J. Kneppers, C.C.G. Benschop. The DNAxs software suite: A three-year retrospective study on the development, architecture, testing and implementation in forensic casework. Forensic Sci. Int. Reports 3 (2021) 100212.’
   
• Hoogenboom J, Sijen T, Benschop C. ProbRank: An efficient DNA database search method for complex mixtures per a quantitative likelihood ratio model. Forensic Sci Int Genet. 2023 Jul;65:102884. doi: https://doi.org/10.1016/j.fsigen.2023.102884
   
• Corina C.G. Benschop, Martin Slagter, Jord H.A. Nagel, Pauline Hovers, Sietske Tuinman, Francisca E. Duijs, Laurens J.W. Grol, Mariëlle Jegers, Abigayle Berghout, Anne-Wil van der Zwan , Rolf J.F. Ypma, Jeroen de Jong, Alexander L.J. Kneppers. Development and validation of a fast and automated DNA identification line. Forensic Sci Int Genet. September 2022, 60:102738. doi: https://doi.org/10.1016/j.fsigen.2022.102738
   
• Corina C.G. Benschop, Martin Slagter, Sophie Smit, Alexander L.J. Kneppers. Automated DNA casework workflow: A retrospective study of the first implementation of FIDL at the Netherlands Forensic Institute. Forensic Sci Int Genet. December 2022, 8: 202210054  doi:[A1] [SK2]  https://doi.org/10.1016/j.fsigss.2022.10.054
   
• Corina C.G. Benschop, Martin Slagter, Laurens J.W. Grol, Pauline Hovers, Jord H.A. Nagel, Sophie Smit, Francisca E. Duijs, Alexander L.J. Kneppers. Fast DNA reports for investigative leads in casework practice: An automated workflow for mixture analysis using database searching based on probabilistic genotyping. Forensic Science International: Synergy, Volume 11, 100632.doi: https://doi.org/10.1016/j.fsisyn.2025.100632
   

DNAxs (including DNAStatistX) is available for test/evaluation purposes for a period of 30 days and can be requested at dnaxs@nfi.nl. The software can only be offered to non-commercial (inter) governmental laboratories. Request a copy through DNAxs@NFI.nl.

For the standalone version of DNAStatistX also contact DNAxs@NFI.nl for a free copy.

For more information on DNAxs read our flyer and the Frequently Asked Questions.

Announcements of DNAxs workshops will be posted here once they are planned:

DNAxs Workshop (9-11 March 2027)