Forensic Science International: Genetics Supplement Series最新文献

The prediction of externally visible characteristics (EVCs) is a commonly used practice by the forensic sciences as an important resource in the investigation of criminal cases in which the identity of perpetrators or victims is unknown or even to recognize decomposed cadavers. With this purpose, genetic markers associated with pigmentation traits have been widely studied by forensic scientists and, nowadays, it is possible to predict phenotypic characteristics such as hair, eyes and skin colour, as well as the presence of skin freckles by analysing single nucleotide polymorphisms (SNPs). In this study, we analysed the association of six SNPs located in pigmentation genes to the presence of freckles in individuals from the Brazilian population for forensic DNA phenotyping. The study was based within the context of a larger project on a population sample of 534 adult Brazilians of both sexes and different skin colours. DNA was extracted from peripheral blood and genotyped using the TaqMan® OpenArray® Real-Time PCR System (ThermoFischer Scientific) technique. Statistical analyses were carried out with the R software (version 4.0.2). As for the results obtained, three SNPs were shown to be statistically associated to the freckling, rs12203592, rs1800404 and rs222847, with CT, AG and AA genotypes being the main contributors, respectively. Variables such as sex of the individuals and skin colour were found to also contribute to the manifestation of this pigmentation trait. Further statistical analyses will be carried out to evaluate the possibility of using the SNPs in this study for phenotyping prediction of the Brazilian population, improving existing DNA phenotyping models in forensic sciences.

The new Applied Biosystems™ SeqStudio ™ Flex Series Genetic Analyzer have improved the benchmark for research use only for Capillary Electrophoresis (CE) by providing innovative approaches to enhanced hand-free operation, flexibility, ease of use, data quality and connectivity. This newly designed 8 or 24 capillary system supports fragment sizing and DNA sequencing applications providing scientists with medium throughput technology for use in research applications. The steps from system set-up to size or base-called data have been simplified with hardware functionality and user-friendly software enhancements designed into this new CE system.

We will discuss innovations related to ease of use including one button start-up, an on-board computer with touchscreen, intuitive software, easier to use capillary arrays, and desktop and cloud-based plate manager software. Innovations related to increased flexibility include continuous plate loading, automated plate linking that be able to maintain traceability from sample to result when using barcoded plates, urgent sample reprioritization, fragment and sequencing samples be run on the same plate, and multi-user support will also be discussed. In addition, gold standard fragment analysis and sequencing data quality has been enhanced through innovative algorithms providing autospectral calibrations, and off-scale recovery of data for fragment analysis. Innovative service and support functionality including remote troubleshooting with instrument system login capability, and on-board instrument help videos are included. Finally, we will touch upon new connectivity, which includes Thermo Fisher connect for remote monitoring, analysis, and data sharing as well as other functionality such as voice commands and Wi-Fi capability that the system will provide. The following summarizes highlights from the developmental validation performed to demonstrate the functionality of SeqStudio ™ Flex Series Genetic Analyzer.

Analysis of DNA from burnt bone fragment is the very hard work for the human identification in forensic casework. In general, cremated bone with an artificial damage is more difficult to get an intact DNA than a singed one because of the chemical and biological drastic changes such as protein denaturation and destruction. In this study, we pursue the best technical approach for the minimal damage and the contamination of DNA from other factors in the preconditioning and the extraction process based on over 70 years old Korean War victim skeletal that was burnt and buried in Korean Peninsula. First of all, we removed the pollutant and the dust from the burnt bones using dental instruments, and then incubated with EDTA buffer at 25 ℃ to remove inhibitors such as calcium and mineral. In order to compare the DNA preservation ability between a pellet and a supernatant, samples are repeatedly tested to collect washed EDTA buffer several times to separate. Each of isolated materials is secondly cleaned with the organic extraction method using phenol and analyzed mtDNA sequence with the in-house method for the ancestry assay. The better discrimination ability was appeared in the supernatant than the pellet. Nevertheless, many of the forensic geneticists use a powdering method for getting more DNA, we applied EDTA buffer in the preconditioning step to eliminate every contamination. As a result, the contamination factor was efficiently removed and the ancestry was estimated as per the written information. Consequently, cremated bone is identified to belong in the D4 mtDNA haplogroup which is commonly reported in ethnic groups in Asia especially Korea. This is a preliminary study of a human identification over an ancestry analysis to give information against a mass disaster in a future. Through a higher process optimization and better analytical methods toward more remains, which are genetically difficult to analyze, will support to examine the identity of the post cremated remains.

The aim of this study is to provide an overview of ongoing research on and the development of identification tools for big cats (Panthera tigris, Panthera leo, Panthera pardus, …). The set of tools includes a species-specific RTPCR quantitation system (nuclear and mitochondrial), STR multiplexes, a rapid system for big cat species determination, and a database solution.

The presence of a tri-allelic pattern at a single locus in a multiplex short tandem repeat (STR) profile is a rarely observable event. Generally, based on peak height measured by the capillary electrophoresis (CE) method and combination of alleles, the tri-allelic pattern is distinguishable into two predominant types: type 1 and 2, which are caused, respectively, by somatic mutations and chromosomal rearrangements. When tri-allelic patterns at more than one STR located on the same chromosome are detected, there is a reasonable suspicion of a trisomy due to an extra copy of a chromosome. Therefore, information on the type of three-band pattern is usually limited to STRs localized on the same chromosome included in the forensic kit in use and sometimes in insufficient numbers to classify this event correctly. The opportunity to extend this evaluation to additional markers, such as SNPs detectable using NGS, has not yet been explored. In this study, using the ForenSeq™ DNA Signature Prep kit, two cases of autosomal aneuploidy were revealed on chromosome 21, relying not only on STRs assessment but also extending the analysis to the five identity-informative single nucleotide polymorphisms (iiSNPs) localized on chromosome 21.

Microhaplotypes (MHs) are SNP-based multiallelic loci that have several advantages over individual SNPs and short tandem repeats (STRs). For several years we have been searching for better MHs based on the effective number of alleles at a locus (A_e) and the locus informativeness for population relationships (I_n) with thoughts of incorporating MHs into casework. We genotyped a multiplex of our best 90 MHs on 79 populations. We have ranked the 90 by A_e and analyzed the top 24 to evaluate their potential value in forensic casework. We chose 24 to compare with the popSTR dataset of 20 CODIS markers plus four other STRs commonly typed. PopSTR has full data on 32 populations; our 24 MHs have full data on 79 pops. We have compared the two sets of 24 loci (MH and STR) in four areas: individualization, biogeographic ancestry, kinship analysis, and mixture resolution.

Personal identification in mass disasters and in crimes is essential for humanitarian, ethical and legal reasons. In these contexts, when individuals cannot be identified by standard forensic DNA analysis, the Forensic DNA Phenotyping and the analysis of the biogeographical ancestry could help. The aim of this study was to evaluate the potential of a new panel of 891 SNPs in predicting phenotypic traits and biogeographical origin to create a “biological identikit”. In addition to fresh biological material, old evidence found at the crime scene or extracted and long-term stored DNA were tested with 41 SNPs for phenotyping and 850 SNPs for ancestry. All the SNPs were successfully incorporated into a single two-step multiplex PCR reaction using the IonAmpliSeq ™ Library Plus and applied for massive parallel sequencing with the Ion S5 platform using up to 0.05 ng/µL of DNA. The analysis of the results was carried out with an in-house predictive algorithm and consulting 20 population databases. By comparing the results obtained with identikit or video-photographic surveys, it was possible to predict phenotype and ancestry with an accuracy greater than 90%. While these new markers cannot identify a specific individual, they can be a valuable investigative tool.

The Y-chromosome can be used as an identification method to find paternally related males of the perpetrator. When a close Y-haplotype match is identified, the time to their most recent common ancestor (tMRCA) needs to be estimated to reconstruct their genealogy. To date, two mutation models and three online tMRCA calculators exist. But, they do not include individual mutation rates with multi-step changes, while ignoring hidden multiple, back or parallel modifications. To improve tMRCA estimation, we developed a user-friendly calculator, the ‘YMrCA’, including all previously mentioned mutation characteristics. Here, a case using genealogical pairs with confirmed biological kinships visualizes the good estimation performance of the YMrCA compared to the state-of-the-art. Even when genealogical pairs have equal number of mutations, the YMrCA still estimates the correct number of generations due to the inclusion of individual Y-STR mutation rates and the different mutational influencing factors.

MHinNGS is a Python application developed for analysis of microhaplotypes (MHs) in single-end sequencing data. MHinNGS analyses reads in standard formats and store each sequence into bins, one bin for each MH as defined by the two flanking sequences. MHinNGS requires a reference genome and a configuration file with information about each locus. Four mandatory and 15 optional criteria defined in the configuration file allow detailed locus-specific analyses of the MH loci. The program 1) removes noise, 2) identify and name alleles, 3) test the genotypes, and 4) test unique sequences not identified as noise or alleles. MHinNGS produces a result file, where every unique sequence that passed the noise filter is presented with MH allele, read depth, warning flags based on the genotyping criteria, sequence, heterozygote balance, and MH name. Furthermore, variation in other parts of the fragment that is not defined as SNPs in the MH, linked variants, or rare SNPs are listed in a separate column of the result file.

The use of illicit drugs is a continuing blight on society. Detecting DNA from individuals involved in the manufacturing and distribution of drugs can provide valuable investigative information or strategic intelligence which, in turn, can be used to disrupt the supply and distribution of illicit drugs. Our study details the transfer, persistence, prevalence, and recovery of human DNA on the exterior of tablets and capsules, as well as within drug powders. Various experiments were conducted to mimic stages in the creation and packaging of tablets and capsules. We showed that the act of brief contact (1–3 s) is sufficient to generate informative DNA profiles that can be uploaded and compared to databases internationally. This work complements chemical drug profiling data by linking seizures to each other and individuals via DNA profiles, providing information to prosecution or intelligence agencies. The generation of DNA information from illicit drug preparations is another tool that can be used in the fight against illicit drug manufacture and distribution.