Irina O. Perepechina

The article at an interdisciplinary level deals with the issues of monozygotic twins individualization using forensic DNA identification methods. The problematic area is that STR analysis, which is the basis of expert methods and the creation of genetic databases, produces identical DNA profiles with samples of monozygotic twins. From the perspective of an integrating specialist the legal, statistical and molecular-genetic aspects of the problem are discussed. The consequences of this limitation for the investigation of crimes and legal proceedings in criminal and civil proceedings are demonstrated using examples from practice. It is shown that, given comparable factual circumstances, the court decisions may differ significantly. Data on the frequency of natural birth of monozygotic twins are presented, and a noticeable increase in the frequency of births of monozygotic twins is noted in connection with the use of medical reproductive technologies. It has been substantiated that, despite the initial genetic identity, the accumulation of spontaneous mutations, variability of epigenetic markers, as well as other factors lead to the emergence of differences in monozygotic twins detected by modern technologies. The types of such differences, their molecular mechanisms and prospects for application in criminalistics and forensic medicine for establishing identity and family links are considered. The problems and prospects for further development of identification of monozygotic twins issues are discussed.