Modern possibilities of examination of physical evidence of biological origin in the identification of unidentified corpses and missing persons

Abstract

Mass deaths in wartime require forensic medical examinations to establish the causes of death, identify unidentified corpses and missing persons, and resolve other medical and biological issues of importance to the investigation. Performing these studies in wartime often involves a significant amount of damage to the corpses of the deceased, which in a fairly large number of cases (15%) results in the loss of signs that are significant for identification.The purpose of this work was to analyse existing scientific data and practical experience on modern possibilities for studying physical evidence of biological origin in order to solve expert tasks for identifying unidentified corpses and missing persons to expand knowledge about the possibilities of forensic molecular genetic examination during wartime.The author cites historical facts about the use of Bertillonage, fingerprinting, the discovery and study of DNA, which was at one time a revolutionary breakthrough in the development of forensic medicine and criminalistics.But during hostilities with the predominant use of artillery weapons, strike drones and missiles, the very widespread explosive trauma, which is characterized by polymorphism (mechanical, thermal, chemical effects) of injuries, as well as improper storage of dead bodies for various reasons, explains the impossibility today of using in full the generally accepted methods of forensic medical identification, fingerprinting, research using ultrasound diagnostics of internal organs, comparison of skull photos with photographs taken during life of the missing due to the loss of significant identification features of the corpse due to its destruction.The author notes in her study that at this stage one of the objective and reliable means of identification is forensic molecular genetic examination (SMGE). Using its technologies, it is possible to examine almost all tissues that contain DNA; biological objects that are contaminated with microflora; microquantities of biological material (only 6–9 nucleated cells are required to establish a high-quality DNA profile, but thanks to the polymerase chain reaction, the nuclear marker regions are amplified in the required quantity); mixed traces, especially in cases of investigation of objects for the fact of committing crimes on a sexual basis, to identify biological samples (bone remains) and biological traces of a missing person. To establish the genetic features of a missing person, it is necessary to remove the personal belongings of this person and send them for examination. After conducting the examination and obtaining a high-quality DNA profile, it is placed in regional or central registers of human genetic features. The central register of human genetic features (COGOL) is formed from DNA profiles of persons involved in criminal proceedings, traces from the scenes of unsolved crimes, unidentified corpses, missing persons and their direct relatives.Analysing the data available in the literature, the author notes that there is an algorithm for carrying out the procedure for identifying an unknown person from their remains based on DNA analysis, which is used in Ukraine by full-profile DNA laboratories:1. Selection of biological material from the remains of an unidentified person.2. Isolation of DNA from this material and its purification.3. Determination of the amount of isolated DNA, assessment of the degree of its degradation and normalization of concentration.4. Amplification of marker sections of nuclear DNA, primarily loci with short tandem repeats (STR, from Short Tandem Repeats), much less often – marker sequences containing sites with single-nucleotide polymorphism (SNP, from Single-Nucleotide Polymorphism).5. Capillary electrophoresis of amplified loci with STR, or sequencing of nuclear or mitochondrial DNA sequences containing SNP.6. Analysis of the obtained electrophoregrams of STR loci and/or chromatograms of nucleotide sequences with SNP, which ends with the establishment of individual molecular genetic features of the corpse of an unknown person.7. Deposit of the established molecular genetic features (mainly DNA profiles of STR loci and sequences with SNP) in genetic information databases. These data are used to generate input queries by the database to search for matches with genetic features of other persons or traces, in particular, possible relatives of an unidentified person.8. Search for matches of the established genetic features of an unknown person with the features of known persons (usually probable close relatives) or with biological traces found on the belongings of a known owner.Based on the results of the search and analysis of matches, a comparative examination is assigned, which, based on statistical assessments, gives a conclusion on the final DNA identification of an unidentified person.