Search

The association of body fluids/cell types and donors in mixed biological traces is an important, but challenging task required to evaluate the value of evidence given forensic propositions concerning the source of the DNA. The linking of a DNA profile with evidence from presumptive tests or RNA analysis is not straightforward. Coding region SNPs (cSNPs) are a novel type of evidential markers that are both cell type specific and individual specific. They thereby provide a direct link between a donor and a body fluid in mixed biological stains. In this proof-of-concept paper we consider the evaluation of cSNP profiles given source level propositions and explore the use of the open-source software EuroForMix to compute likelihood ratios. The discrimination power of the cSNPs for various body fluids is investigated with simulations. We provide case examples where the type of biological material is questioned and where cSNP profiles can be used to assign a donor to a body fluid, and discuss how the results can be reported in court.

Knowledge about the age of a stain, also termed as time since deposition (TsD), would provide law-enforcing authorities with valuable information for the prosecution of criminal offenses. Yet, there is no reliable method for the inference / assessment of TsD available. The aim of this study was to gain further insight into the RNA degradation pattern of forensically relevant body fluids and to find candidate markers for TsD estimation. Blood, menstrual blood, saliva, semen and vaginal secretion samples were exposed to indoor (dark, room temperature) and outdoor (exposed to sun, wind, etc. but protected from rain) conditions for up to 1.5 years. Based on expression and degradation analyses, we were able to identify body fluid specific signatures and RNA degradation patterns. The indoor samples showed a marked drop in RNA integrity after 6 months, while the outdoor samples were difficult to interpret and therefore excluded for some of the analyses. Up to 4 weeks, indoor samples showed more stable and less degrading transcripts than outdoor samples. Stable transcripts tended to be significantly shorter than degrading ones or transcripts, which are neither degrading nor stable. We reinforced the body fluid specific and the housekeeping gene nature of previously reported markers. With an unbiased approach, we selected stable and degrading genes for each body fluid in the short term and assessed their integrity during extended storage. We identified several stable and degrading gene transcripts, which could be tested in a targeted assay to assess the TsD interval e.g. by analyzing the ratio of degrading vs stable transcripts. In conclusion, we were able to detect RNA degradation patterns in samples being aged up to 1.5 years and identified several candidate markers, which could be evaluated for TsD estimation. ISSN:1872-4973 ISSN:1878-0326

Collection of touch DNA from an offender on the victim's skin can provide relevant evidence for investigations of criminal cases. Therefore, the choice of the optimal sample collection method is crucial. In this study, we investigated the recovery of STR profiles from touch DNA on human skin by comparing nine different collection methods: the dry and wet cotton swabs in three different movements, the double-swab (wet-dry) method, the wet and dry Copan FLOQSwabs™, and the Scene Safe FAST™ minitapes. Mock assault scenarios were conducted with a male offender grasping the forearms of a female victim. Samples were collected from the assaulted area of the victim's skin, and the recovery of the offender's STR profile was evaluated. Our results indicate that the different swabs and swabbing techniques did not have a distinct impact on the STR recovery; however, the lowest STR recovery was achieved with Scene Safe FAST™ minitapes. In addition, we compared the double-swab method to the single-swab method by analyzing the DNA quantity of the wet and dry swabs separately. We found on average 13.7% more offender DNA using the double-swab method, but this did not translate into higher STR recovery. Our findings indicate that several methods perform equally well when collecting touch DNA from human skin, although SceneSafe FAST™ minitapes seem to be the least adequate for this purpose.

The application of transcriptome analyses in forensic genetics has experienced tremendous growth and development in the past decade. The earliest studies and main applications were body fluid and tissue identification, using targeted RNA transcripts and a reverse transcription endpoint PCR method. A number of markers have been identified for the forensically most relevant body fluids and tissues and the method has been successfully used in casework. The introduction of Massively Parallel Sequencing (MPS) opened up new perspectives and opportunities to advance the field. Contrary to genomic DNA where two copies of an autosomal DNA segment are present in a cell, abundant RNA species are expressed in high copy numbers. Even whole transcriptome sequencing (RNA-Seq) of forensically relevant body fluids and of postmortem material was shown to be possible. This review gives an overview on forensic transcriptome analyses and applications. The methods cover whole transcriptome as well as targeted MPS approaches. High resolution forensic transcriptome analyses using MPS are being applied to body fluid/ tissue identification, determination of the age of stains and the age of the donor, the estimation of the post-mortem interval and to post mortem death investigations.

Current body fluid identification methods do not reveal any information about the time since deposition (TsD) of biological traces, even though determining the age of traces could be crucial for the investigative process. To determine the utility of microbial RNA markers for TsD estimation, we examined RNA sequencing data from five forensically relevant body fluids (blood, menstrual blood, saliva, semen, and vaginal secretion) over seven time points, ranging from fresh to 1.5 years. One set of samples was stored indoors while another was exposed to outdoor conditions. In outdoor samples, we observed a consistent compositional shift, occurring after 4 weeks: this shift was characterized by an overall increase in non-human eukaryotic RNA and an overall decrease in prokaryotic RNA. In depth analyses showed a high fraction of tree, grass and fungal signatures, which are characteristic for the environment the samples were exposed to. When examining the prokaryotic fraction in more detail, three bacterial phyla were found to exhibit the largest changes in abundance, namely Actinobacteria, Proteobacteria and Firmicutes. More detailed analyses at the order level were done using a Lasso regression analysis to find a predictive subset of bacterial taxa. We found 26 bacterial orders to be indicative of sample age. Indoor samples did not reveal such a clear compositional change at the domain level: eukaryotic and prokaryotic abundance remained relatively stable across the assessed time period. Nonetheless, a Lasso regression analysis identified 32 bacterial orders exhibiting clear changes over time, enabling the prediction of TsD. For both indoor and outdoor samples, a larger number (around 60%) of the bacterial orders identified as indicative of TsD are part of the Actinobacteria, Proteobacteria and Firmicutes. In summary, we found that the observed changes across time are not primarily due to changes associated with body fluid specific bacteria but mostly due to accumulation of bacteria from the environment. Orders of these environmental bacteria could be evaluated for TsD prediction, considering the location and environment of the crime scene. However, further studies are needed to verify these findings, determine the applicability across samples, replicates, donors, and other variables, and also to further assess the effect of different seasons and locations on the samples. ISSN:1872-4973 ISSN:1878-0326

Ancient DNA (aDNA) analysis is a powerful tool in multidisciplinary research on human remains, potentially leading to kinship scenarios and historical identifications. In this study, we present a genetic investigation of three noble families from the 17th to 19th centuries AD entombed in burial crypts at the cloister church of Riesa (Germany). Tests were aimed at identifying anticipated and incidental genetic relationships in our sample and the implications thereof for the assumed identity of the deceased. A total of 17 individuals were investigated via morphological, radiographic and aDNA analysis, yielding complete and partial autosomal and Y-STR profiles and reliable mtDNA sequences. Biostatistics and lineage markers revealed the presence of first to third degree relationships within the cohort. The pedigrees of the families Hanisch/von Odeleben and von Welck were thereby successfully reproduced, while four previously unknown individuals could be linked to the von Felgenhauer family. However, limitations of biostatistical kinship analysis became evident when the kinship scenario went beyond simple relationships. A combined analysis with archaeological data and historical records resulted in (almost) unambiguous identification of 14 of the 17 individuals.

In a previous EUROFORGEN/EDNAP collaborative exercise, we tested two assays for targeted mRNA massively parallel sequencing for the identification of body fluids/tissues, optimized for the Illumina MiSeq/FGx and the Ion Torrent PGM/S5 platforms, respectively. The task of the second EUROFORGEN/EDNAP collaborative exercise was to analyze dried body fluid stains with two different multiplexes, the former Illumina 33plex mRNA panel for body fluid/tissue identification and a 35plex cSNP panel for assignment of body fluids/tissues to donors that was introduced in a proof-of-concept study recently. The coding region SNPs (cSNPs) are located within the body fluid specific mRNA transcripts and represent a direct link between the body fluid and the donor. We predicted the origin of the stains using a partial least squares discriminant analysis (PLS-DA) model, where most of the single source samples were correctly predicted. The mixed body fluid stains showed poorer results, however, at least one component was predicted correctly in most stains. The cSNP data demonstrated that coding region SNPs can give valuable information on linking body fluids/tissues with donors in mixed body fluid stains. However, due to the unfavorable performance of some cSNPs, the interpretation remains challenging. As a consequence, additional markers are needed to increase the discrimination power in each body fluid/tissue category.

In recent years, forensic mRNA profiling has increasingly been used to identify the origin of human body fluids. By now, several laboratories have implemented mRNA profiling and also use it in criminal casework. In 2018 the FoRNAP (Forensic RNA Profiling) group was established among a number of these laboratories with the aim of sharing experiences, discussing optimization potential, identifying challenges and suggesting solutions with regards to mRNA profiling and casework. To compare mRNA profiling methods and results a collaborative exercise was organized within the FoRNAP group. Seven laboratories from four countries received 16 stains, comprising six pure body fluid / tissue stains and ten mock casework samples. The laboratories were asked to analyze the provided stains with their in-house method (PCR/CE or MPS) and markers of choice. Five laboratories used a DNA/RNA co-extraction strategy. Overall, up to 11 mRNA markers per body fluid were analyzed. We found that mRNA profiling using different extraction and analysis methods as well as different multiplexes can be applied to casework-like samples. In general, high input samples were typed with high accuracy by all laboratories, regardless of the method used. Irrespective of the analysis strategy, samples of low input or mixed stains were more challenging to analyze and interpret since, alike to DNA profiling, a higher number of markers dropped out and/or additional unexpected markers not consistent with the cell type in question were detected. It could be shown that a plethora of different but valid analysis and interpretation strategies exist and are successfully applied in the Forensic Genetics community. Nevertheless, efforts aiming at optimizing and harmonizing interpretation approaches in order to achieve a higher consistency between laboratories might be desirable in the future. The simultaneous extraction of DNA alongside RNA showed to be an effective approach to identify not only the body fluid present but also to identify the donor(s) of the stain. This allows investigators to gain valuable information about the origin of crime scene samples and the course of events in a crime case.

In this study, we have screened the six most relevant forensic body fluids / tissues, namely blood, semen, saliva, vaginal secretion, menstrual blood and skin, for miRNAs using a whole miRNome massively parallel sequencing approach. We applied partial least squares (PLS) and linear discriminant analysis (LDA) to predict body fluids based on the expression of the miRNA markers. We estimated the prediction accuracy for models including different subsets of miRNA markers to identify the minimum number of markers needed for sufficient prediction performance. For one selected model consisting of 9 miRNA markers we calculated their importance for prediction of each of the six different body fluid categories.

Analysis of biological evidence typically begins with a preliminary screening for the presence of biological fluids, traditionally with enzymatic or immunologic tests and of late by RNA profiling. The goal of this study was to create a whole transcriptome protocol, to view potential degradation effects in forensically relevant body fluids. Total RNA from fresh and aged blood, menstrual blood, saliva, semen, skin and vaginal secretion was analyzed with a massively parallel sequencing method. Two RNA-Seq library protocols with and without rRNA depletion were tested and compared. The rRNA depletion step had a negative influence on the sequencing quality and on the downstream analyses. From the human and bacterial RNA sequences, source-specific signatures could be identified. Aged samples showed in general a higher level of RNA degradation and decreased bacterial diversity. In summary, we could show that transcriptional profiling and metagenome analysis are powerful tools to provide additional information about the trace evidence.

Jorg Jenatsch was a Swiss defender of independence and a fighter for liberty in the 17th century. With the help of three living male members of the Jenatsch family, we successfully identified a skeleton exhumed from Chur cathedral as the remains of Jorg Jenatsch. Our conclusion was based upon complete Y-STR and Y-SNP profiles that could be generated by replicate analyses of a bone sample available to us. The skeleton and the three living family members carried the same Y-SNP haplogroup, but were discordant at three of 23 Y-STR loci. This notwithstanding, conservative biostatistical evaluation of the data suggests that the Chur skeleton is at least 20 times more likely than not to be Jorg Jenatsch.

In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent. Fil: Corach, Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Caputo, Mariela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Marino, Miguel Eduardo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Laboratorio de Analisis de ADN; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Purps, Josephine. Charité-Universitätsmedizin; Alemania Fil: Siegert, Sabine. University of Cologne; Alemania Fil: Willuweit, Sascha. Charité-Universitätsmedizin; Alemania Fil: Nagy, Marion. Charité-Universitätsmedizin; Alemania Fil: Alves, Cíntia. Universidad de Porto; Portugal Fil: Salazar, Renato. Universidad de Porto; Portugal Fil: Angustia, Sheila M. T.. Philippine National Police Crime Laboratory; Filipinas Fil: Santos, Lorna H.. Philippine National Police Crime Laboratory; Filipinas Fil: Anslinger, Katja. Universitat Genzentrum Der Ludwing-maximilians; Alemania Fil: Bayer, Birgit. Universitat Genzentrum Der Ludwing-maximilians; Alemania Fil: Ayub, Qasim. The Wellcome Trust Sanger Institute; Reino Unido Fil: Wei, Wei. The Wellcome Trust Sanger Institute; Reino Unido Fil: Xue, Yali. The Wellcome Trust Sanger Institute; Reino Unido Fil: Tyler Smith, Chris. The Wellcome Trust Sanger Institute; Reino Unido Fil: Baeta Bafalluy, Miriam. Universidad de Zaragoza; España Fil: Martínez Jarreta, Begoña. Universidad de Zaragoza; España Fil: Egyed, Balazs. Eotvos University, Budapest; Argentina Fil: Balitzki, Beate. Universidad de Basilea; Suiza Fil: Tschumi, Sibylle. Universidad de Basilea; Suiza Fil: Ballard, David. King; Reino Unido Fil: Syndercombe Court, Denise. King; Reino Unido Fil: Barrantes, Xinia. Poder Judicial, Forensic Sciences Department; Costa Rica Fil: Bäßler, Gerhard. Landeskriminalamt Baden-Württemberg; Alemania Fil: Berger, Burkhard. Universidad de Innsbruck; Austria Fil: Niederstätter, Haral. Universidad de Innsbruck; Austria Fil: Parson, Walther. Universidad de Innsbruck; Austria. University Park; Estados Unidos Fil: Davis, Carey. Department of Molecular and Medical Genetics; Estados Unidos. Institute of Applied Genetics; Estados Unidos Fil: Furfuro, Sandra. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Laboratorio de Análisis de ADN; Argentina Fil: Locarno, Laura. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Laboratorio de Análisis de ADN; Argentina