Abstract
BackgroundCommercial kits for Human Identification (HID) purposes, based on 15 short tandem repeat (STR) regions, allow the resolution of most forensic and paternity cases. However, some pitfalls arise in situations such as identification of missing persons, disaster victims, and in motherless paternities. We describe nine fortuitous matches found during the inclusion of new DNA profiles and/or searching for missing persons within a Mexican STR database (N = 2000). For these cases, we estimated both the likelihood ratio (LR) and the modified LR according to National Research Council (NRC) recommendations (i.e., LRNRC).ResultsIn most cases, low LRNRC values (~1 or <1) and elevated presence of modal STR alleles (>50% loci) were indicative of fortuitous matches. We estimated a significant increase in the observed frequency of fortuitous matches in this database when using the PowerPlex 16 DNA-typing system. In addition, forensic efficiency parameters for this HID kit are reported for the State of Mexico based on a population sample selected from the STR database (n = 493). We describe the population structure and relationships, which detail comparative homogeneity among Mexican-Mestizos from the Central region, excluding the Western region.ConclusionsThe results suggest that additional / more powerful HID systems should be used when searching for relatives within STR databases in order to enable definitive conclusions, which are also required in cases of motherless paternity and massive disasters. The genetic structure described herein allows forensic geneticists to use alternative STR population data during statistical interpretation, given that most Mexican populations do not have their own STR databases.
Highlights
Short tandem repeat (STR) loci are the most informative genetic markers used worldwide for human identification (HID) purposes
Observed cases of fortuitous matching We report nine matches found during the search or inclusion of DNA profiles into the short tandem repeat (STR) database of 2000 samples from the State of Mexico
The small number of cases presented limits the application of statistical tests, the results suggest those STRs that could be involved in fortuitous matches by their allele distribution, confirming their elevated presence (>50% loci) in most of the reported fortuitous matches (>55% cases)
Summary
Short tandem repeat (STR) loci are the most informative genetic markers used worldwide for human identification (HID) purposes. The lack of informative reference samples (first-degree relatives) is probably the most common problem when identifying unknown bodies This is sometimes overcome by searching STR databases that include samples from missing persons and their relatives, criminals, victims, etc. Commercial kits for Human Identification (HID) purposes, based on 15 short tandem repeat (STR) regions, allow the resolution of most forensic and paternity cases. We describe nine fortuitous matches found during the inclusion of new DNA profiles and/or searching for missing persons within a Mexican STR database (N = 2000). For these cases, we estimated both the likelihood ratio (LR) and the modified LR according to National Research Council (NRC) recommendations (i.e., LRNRC). We describe the population structure and relationships, which detail comparative homogeneity among Mexican-Mestizos from the Central region, excluding the Western region
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
