Next-generation DNA Sequencing in the Mirror of Law Enforcement

Abstract

Next-generation sequencing (NGS) also known as massively parallel sequencing (MPS) has been increasingly important in recent years not exclusively in clinical applications, but also in criminal investigations. Several kits (chemical packages) validated for forensics are now available from manufacturers. Since 2022, one of those kits examining a wide range of STR markers has been introduced into the portfolio of accredited analytical methods in the Hungarian Institute for Forensic Sciences (HIFS). During the internal laboratory validation of the Precision ID GlobalFiler NGS STR Panel v2 kit all quality measures and setting parameters were determined to make the technology available for routine forensic investigations. In the Institute a comprehensive population genetic analysis has been launched to create a representative allele frequency database of the Hungarian population to support the statistical interpretation, in court, of the results generated by the new genetic method. The other aim of the study was to assess the backward compatibility and divergence of the new technology to the traditional capillary electrophoresis. In order to build up the population database 200 volunteer samples were analysed by the new MPS-STR method until now to create a first version allele frequency database. The developed population database is crucial for the biostatistical calculation and interpretation to measure the weight of evidence in forensic cases. Using the new technology, the increased variability of the observed alleles in the database will elevate the power of discrimination of each genetic evidence. According to recent experience the new MPS technology can be applied to analyse highly degraded and low copy number DNA samples as well.