APPLICATION OF THE NEW MULTIPLEX STR SYSTEMS IN FORENSIC DNA ANALYSIS OF SKELETAL REMAINS IN HUMAN IDENTIFICATION CASES

Various forensic techniques are used to identify a human corpse, depending on the circumstances and the state of remains. Unfortunately, the standard forensic identification methods were not sufficient in 30 to 35 % of all victims, therefore DNA identification was necessary. Since the beginning of our work in 2003, our laboratory has focused exclusively on STR DNA from bone, a powerful tool in missing person cases. 92% of skeletal remains analyzed were samples submitted for body identifications by law enforcement and only 8% were samples submitted to answer family identity or historical questions. In order to expand DNA typing capabilities on challenging samples such as bones, teeth, poorly preserved corpses, such as those found in water, buried or burned; modifications were introduced in protocols Phenol Chloroform Isoamyl Alcohol (PCIA) Extraction methods – organic extraction method and extraction PrepFiler® BTA Forensic DNA Extraction Kit (Applied Biosystems) enabled obtaining profiles in 98% cases. We have followed the standardization process used in Europe and the recommendations of the European Network of Forensic Science Institutes (ENFSI) for adoption of new genetic markers through the application of new STR multiplex systems in the DNA analysis. In this paper we have presented 30 bone samples of skeletal remains from routine casework submitted for body identifications by law enforcement, which were analyzed through the application of new STR multiplex system using Investigator® 24plex QS kit and GlobalFiler™ PCR Amplification kit, previously analyzed AmpFLSTR® Identifiler® Plus kit. Advanced extraction and purification techniques, together with more sensitive and robust new amplification kits allowed us to overcome the challenges associated with processing compromised skeletal remains and ultimately obtain full STR DNA profiles in 99% of the bones.