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Arsenault H, Kuffel A, Daeid NN, Gray A. Trace DNA and its persistence on various surfaces: A long term study investigating the influence of surface type and environmental conditions - Part one, metals. Forensic Sci Int Genet 2024; 70:103011. [PMID: 38324952 DOI: 10.1016/j.fsigen.2024.103011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/09/2024]
Abstract
It is imperative for proper evidence triage that forensic biologists understand what kind of results to expect from certain evidence types submitted for DNA analysis. The persistence of trace DNA has been insufficiently investigated and there is little data available pertaining to the persistence of DNA in different environmental conditions and on different materials. The goal of this study is to increase the available data on this topic which would, in turn, help forensic biologists manage expectations when submitting specific evidence types for DNA testing. The work presented herein is a large-scale persistence project aimed to identify trends in the persistence of trace DNA and indicate how different environmental storage conditions and target surface characteristics influence the persistence of cellular and cell free DNA (cfDNA) over time. To eliminate variation within the experiment we used a proxy DNA deposit consisting of a synthetic fingerprint solution, cellular DNA, and/or cfDNA. Samples were collected and analysed from 7 metals over the course of 1 year (27 time points) under 3 different environmental storage conditions. The results of this experiment show that metal type greatly influences DNA persistence. For instance, copper exhibited an expected poor DNA persistence (up to 4 h) which a purification step did not help increase the DNA yield. Alternatively, DNA can persist for up to a year on lead at levels potentially high enough to allow for forensic DNA testing. Additionally, this study showed that the sample storage environment had no impact on DNA persistence in most cases. When considering DNA type, cfDNA was shown to persist for longer than cellular DNA and persistence as a whole appears to be better when DNA is deposited as mixtures over when deposited alone. Unsurprisingly, it can be expected that DNA recovery rates from trace deposits will decrease over time. However, DNA decay is highly dependent on the metal surface and extremely variable at short time points but slightly less variable as time since deposition increases. This data is intended to add to our understanding of DNA persistence and the factors which affect it.
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Affiliation(s)
- Hilary Arsenault
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK.
| | - Agnieszka Kuffel
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
| | - Niamh Nic Daeid
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
| | - Alexander Gray
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
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2
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Jansson L, Siti C, Hedell R, Forsberg C, Ansell R, Hedman J. Assessing the consistency of shedder status under various experimental conditions. Forensic Sci Int Genet 2024; 69:103002. [PMID: 38176092 DOI: 10.1016/j.fsigen.2023.103002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/15/2023] [Accepted: 12/16/2023] [Indexed: 01/06/2024]
Abstract
Shedder status is defined as the propensity of an individual to leave DNA behind on touched items or surfaces and has been suggested as one of the major factors influencing DNA transfer. However, little is known about whether shedder status is a constant property of an individual across multiple measurements or when the environmental conditions are changed. We have assessed DNA depositions of six males on 20 occasions to acquire a reference data set and to classify the participants into high, intermediate, or low shedders. This data set was also used to investigate how the probability of a correct shedder status classification changed when the number of DNA deposition measurements increased. Individual sweat rates were measured with a VapoMeter and data regarding hygiene routines were collected through a questionnaire on each sampling occasion. Next, we investigated how changes in the experimental conditions such as seasonal variation, hygiene routines, the temperature of the touched object, and repeated handling of an object influenced the DNA shedding. Additionally, we assessed DNA collected from the face and from T-shirts worn by the six participants to explore whether shedder status may be associated with the relative amount of DNA obtained from other body parts. Our results indicate that shedder status is a stable property across different seasons and different temperatures of handled objects. The relative DNA amounts obtained from repeatedly handled tubes, worn T-shirts, and from faces reflected the shedder status of the participants. We suggest that an individual's shedder status is highly influenced by the DNA levels on other body parts than hands, accumulating on the palms by frequently touching e.g., the face or previously handled items harboring self-DNA. Assessing physiological differences between the participants revealed that there were no associations between DNA shedding and individual sweat rates.
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Affiliation(s)
- Linda Jansson
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Chiara Siti
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Ronny Hedell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden
| | | | - Ricky Ansell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Department of Physics, Chemistry and Biology, IFM, Linköping University, Linköping, Sweden
| | - Johannes Hedman
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
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3
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Gentry AE, Ingram S, Philpott MK, Archer KJ, Ehrhardt CJ. Preliminary assessment of three quantitative approaches for estimating time-since-deposition from autofluorescence and morphological profiles of cell populations from forensic biological samples. PLoS One 2023; 18:e0292789. [PMID: 37824498 PMCID: PMC10569564 DOI: 10.1371/journal.pone.0292789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
Determining when DNA recovered from a crime scene transferred from its biological source, i.e., a sample's 'time-since-deposition' (TSD), can provide critical context for biological evidence. Yet, there remains no analytical techniques for TSD that are validated for forensic casework. In this study, we investigate whether morphological and autofluorescence measurements of forensically-relevant cell populations generated with Imaging Flow Cytometry (IFC) can be used to predict the TSD of 'touch' or trace biological samples. To this end, three different prediction frameworks for estimating the number of day(s) for TSD were evaluated: the elastic net, gradient boosting machines (GBM), and generalized linear mixed model (GLMM) LASSO. Additionally, we transformed these continuous predictions into a series of binary classifiers to evaluate the potential utility for forensic casework. Results showed that GBM and GLMM-LASSO showed the highest accuracy, with mean absolute error estimates in a hold-out test set of 29 and 21 days, respectively. Binary classifiers for these models correctly binned 94-96% and 98-99% of the age estimates as over/under 7 or 180 days, respectively. This suggests that predicted TSD using IFC measurements coupled to one or, possibly, a combination binary classification decision rules, may provide probative information for trace biological samples encountered during forensic casework.
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Affiliation(s)
- Amanda Elswick Gentry
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Sarah Ingram
- Department of Forensic Science, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - M. Katherine Philpott
- Department of Forensic Science, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kellie J. Archer
- Division of Biostatistics, College of Public Health, The Ohio State University, Columbus, Ohio, United States of America
| | - Christopher J. Ehrhardt
- Department of Forensic Science, Virginia Commonwealth University, Richmond, Virginia, United States of America
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4
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Ingram S, DeCorte A, Gentry AE, Philpott MK, Moldenhauer T, Stadler S, Steinberg C, Millman J, Ehrhardt CJ. Differentiation of vaginal cells from epidermal cells using morphological and autofluorescence properties: Implications for sexual assault casework involving digital penetration. Forensic Sci Int Genet 2023; 66:102909. [PMID: 37399646 PMCID: PMC10528675 DOI: 10.1016/j.fsigen.2023.102909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/16/2023] [Accepted: 06/22/2023] [Indexed: 07/05/2023]
Abstract
Analysis of DNA mixtures from sexual assault evidence is an ongoing challenge for DNA casework laboratories. To assist the forensic scientist address source and activity level propositions there is a significant need for new techniques that can provide information as to the source of DNA, particularly for sexual assault samples that do not involve semen. The goal of this study was to develop a new biological signature system that provides additional probative value to samples comprised of mixtures of epidermal and vaginal cells, as may be observed in cases involving digital penetration. Signatures were based on morphological and autofluorescence properties of individual cells collected through Imaging Flow Cytometry (IFC). Comparisons to reference cell populations from vaginal tissue and epidermal cells collected from hands showed strong multivariate differences across > 80 cellular measurements. These differences were used to build a predictive framework for classifying unknown cell populations as originating from epithelial cells associated with digital penetration or epidermal tissue. As part of the classification scheme, posterior probabilities of specific tissue group membership were calculated for each cell, along with multivariate similarity to that tissue type. We tested this approach on cell populations from reference tissue as well as mock casework samples involving hand swabbings following digital vaginal penetration. Many more cells classifying as non-epidermal tissue were detected in digital penetration hand swab samples than control hand swabbings. Minimum interpretation thresholds were developed to minimize false positives; these thresholds were also effective when screening licked hands, indicating the potential utility of this method for a variety of biological mixture types and depositional events relevant to forensic casework. Results showed that samples collected subsequent to digital penetration possessed markedly higher numbers of cells classifying as vaginal tissue as well as higher posterior probabilities for vaginal tissue (≥ 0.90) compared to cell populations collected from hands without prior contact with vaginal tissue. Additionally, digital penetration cell populations may be resolved from saliva cell populations and other non-target tissue types.
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Affiliation(s)
- Sarah Ingram
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Arianna DeCorte
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Amanda Elswick Gentry
- Virginia Institute for Psychiatric and Behavioral Genetics, Department of Psychiatry, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - M Katherine Philpott
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Taylor Moldenhauer
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Sonja Stadler
- Centre of Forensic Sciences, 70 Foster Drive, Sault Ste. Marie, Ontario, P6A 6V3, Canada
| | - Cory Steinberg
- Centre of Forensic Sciences, 70 Foster Drive, Sault Ste. Marie, Ontario, P6A 6V3, Canada
| | - Jonathan Millman
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada
| | - Christopher J Ehrhardt
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA.
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5
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Arsenault H, Nic Daeid N, Gray A. A synthetic fingerprint solution and its importance in DNA transfer, persistence and recovery studies. Forensic Sci Int Synerg 2023; 6:100330. [PMID: 37249970 PMCID: PMC10209804 DOI: 10.1016/j.fsisyn.2023.100330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/20/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023]
Abstract
A review of the literature on DNA transfer and persistence highlights many difficulties that are encountered when conducting research of this nature. One of the main problems highlighted repeatedly in the literature is the prevalence of inherent uncontrolled variation that accompany these studies, and in turn, the results obtained. This work aims to decrease the amount of intrinsic variability associated with DNA transfer and persistence experiments using a realistic proxy solution which is adaptable, of known composition, reproducible, and capable of being standardised. This proxy is composed of three parts: a synthetic fingerprint solution, cellular DNA, and cell free DNA. In this proof-of-concept study the proxy was tested with a small-scale DNA transfer and recovery experiment and the data obtained suggests that the use of a solution that mimics real fingerprint secretions, over an alternative (such as buffer or a body fluid), is important when working with non-donor provided trace DNA samples. This is because the DNA deposit solution likely impacts the transfer of DNA from fingers/hands to a surface as well as the ability to recover the biological material once deposited.
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6
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Ingram S, DeCorte A, Gentry A, Philpott MK, Moldenhauer T, Stadler S, Steinberg C, Millman J, Ehrhardt CJ. Differentiation of vaginal cells from epidermal cells using morphological and autofluorescence properties: Implications for sexual assault casework involving digital penetration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534941. [PMID: 37034789 PMCID: PMC10081290 DOI: 10.1101/2023.03.30.534941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Analysis of DNA mixtures from sexual assault evidence is an ongoing challenge for DNA casework laboratories. There is a significant need for new techniques that can provide information as to the source of DNA, particularly for sexual assault samples that do not involve semen. The goal of this study was to develop a new biological signature system that provides additional probative value to samples comprised of mixtures of epidermal and vaginal cells, as may be observed in cases involving digital penetration. Signatures were based on morphological and autofluorescence properties of individual cells collected through Imaging Flow Cytometry (IFC). Comparisons to reference cell populations from vaginal tissue and epidermal cells collected from hands showed strong multivariate differences across >80 cellular measurements. These differences were used to build a predictive framework for classifying unknown cell populations as originating from epithelial cells associated with digital penetration or epidermal tissue. As part of the classification scheme, posterior probabilities of specific tissue group membership were calculated for each cell, along with multivariate similarity to that tissue type. We tested this approach on cell populations from reference tissue as well as mock casework samples involving digital penetration. Many more cells classifying as non-epidermal tissue were detected in digital penetration samples than control hand swabbings. Minimum interpretation thresholds were developed to minimize false positives; these thresholds were also effective when screening licked hands, indicating the potential utility of this method for a variety of biological mixture types and depositional events relevant to forensic casework. Results showed that samples collected subsequent to digital penetration possessed markedly higher numbers of cells classifying as vaginal tissue as well as higher posterior probabilities for vaginal tissue (≥ 0.90) compared to cell populations collected from hands without prior contact with vaginal tissue. Additionally, digital penetration cell populations may be resolved from saliva cell populations and other non-target tissue types.
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7
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Fernandez-Tejero N, Gauthier Q, Cho S, McCord BR. High-resolution melt analysis for the detection of skin/sweat via DNA methylation. Electrophoresis 2023; 44:371-377. [PMID: 36480207 DOI: 10.1002/elps.202200120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
The determination of tissue type is important when reconstructing a crime scene as skin cells may indicate innocent contact, whereas other types of cells, such as blood and semen, may indicate foul play. Up to now, there has been no specific DNA methylation-based marker to distinguish skin cell DNA from other body fluids. The goal of this study is to develop a DNA methylation-based assay to detect and identify skin cells collected at forensic crime scenes for use in DNA typing. For this reason, we have utilized a DNA methylation chip array-based genome-wide association study to identify skin-specific DNA methylation markers. DNA obtained from skin along with other body fluids, such as semen, saliva, blood, and vaginal epithelia, were tested using five genes that were identified as sites for potential new epigenetic skin markers. Samples were collected, bisulfite converted, and subjected to real-time polymerase chain reaction (PCR) with high-resolution melt analysis. In our studies, when using WDR11, PON2, and NHSL1 assays with bisulfite-modified PCR, skin/sweat amplicons melted at lower temperatures compared to blood, saliva, semen, and vaginal epithelia. One-way analysis of variance demonstrates that these three skin/sweat markers are significantly different when compared with other body fluids (p < 0.05). These results demonstrate that high-resolution melt analysis is a promising technology to detect and identify skin/sweat DNA from other body fluids.
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Affiliation(s)
- Nicole Fernandez-Tejero
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA
| | - Quentin Gauthier
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA
| | - Sohee Cho
- Institute of Forensic Science, Seoul National University College of Medicine, Seoul, South Korea
| | - Bruce R McCord
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA
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8
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Ingram S, Philpott MK, Ehrhardt CJ. Novel cellular signatures for determining time since deposition for trace DNA evidence. FORENSIC SCIENCE INTERNATIONAL GENETICS SUPPLEMENT SERIES 2022. [DOI: 10.1016/j.fsigss.2022.10.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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9
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Miller JM, Lee C, Ingram S, Yadavalli VK, Greenspoon SA, Ehrhardt CJ. Use of hormone-specific antibody probes for differential labeling of contributor cell populations in trace DNA mixtures. Int J Legal Med 2022; 136:1551-1564. [PMID: 36076079 DOI: 10.1007/s00414-022-02887-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/29/2022] [Indexed: 11/27/2022]
Abstract
A significant proportion of casework analyzed by forensic science laboratories is often "touch" or trace forensic DNA evidence, which is deposited through physical contact and is comprised of sloughed epidermal cells. These samples can be challenging to analyze due to low DNA concentrations, frequent degradation, and the presence of cells from multiple individuals in the same sample. To address these challenges, we investigated a new approach for characterizing trace evidence prior to DNA profiling that labels epidermal cells with antibody probes targeting hormone molecules testosterone and dihydrotestosterone (DHT). The goal was to test whether cell populations derived from separate individuals showed different binding efficiencies to hormone probes and, thus, could be used to detect the presence of multiple cell populations. Additionally, we investigated whether antibody probes could be used to isolate contributor cell populations from an epidermal cell mixture and facilitate deconvolution of mixed DNA profiles recovered from touch/trace evidence. Results showed that cell populations from some individuals could differentiated in trace samples based on fluorescence histograms following probe labeling. However, certain pairs of contributors showed largely or completely overlapping histogram profiles and could not be resolved. Preliminary efforts to separate cell populations that could be differentiated with hormone probes with fluorescence-activated cell sorting (FACS) coupled to DNA profiling and probabilistic modeling indicated that it is possible to enrich contributor cell populations from touch/trace samples and produce more probative DNA profiles compared to the original mixture sample. The variability in labeling, differentiation, and physical separation of cell populations may be impacted by similarities in biochemical profiles across some contributors as well as imbalance of contributor DNA quantities in certain mixtures as is typical in casework involving touch/trace evidence. Ultimately, screening and separation of trace DNA samples with this approach may be presumptive and constrained by sample-specific parameters of the original mixture.
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Affiliation(s)
- Jennifer M Miller
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Christin Lee
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Sarah Ingram
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Vamsi K Yadavalli
- Chemical and Life Sciences Engineering, Virginia Commonwealth University, Richmond, VA, USA
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10
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Elwick K, Gauthier Q, Rink S, Cropper E, Kavlick MF. Recovery of DNA from fired and unfired cartridge casings: comparison of two DNA collection methods. Forensic Sci Int Genet 2022; 59:102726. [PMID: 35660851 DOI: 10.1016/j.fsigen.2022.102726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/22/2022] [Accepted: 05/17/2022] [Indexed: 01/14/2023]
Abstract
For over 10 years, various studies have attempted to increase the recovery of DNA from ammunition by modifying the DNA collection, extraction, purification, and amplification procedures, with varying levels of success. This study focused on the "soaking" method of Montpetit & O'Donnell [1] and the "rinse-and-swab" method of Bille et al. [2]. First, testing for the presence of exogenous DNA, 210 boxed cartridges (brass, steel, and nickel-plated) from nine manufacturers were swabbed and DNA was extracted, concentrated, and quantified. Extracts that quantified > 0 ng/µL (44 of 210) were amplified and genotyped with GlobalFiler™. Of those, only one extract yielded two alleles indicating that the manufacturing and packaging of ammunition was virtually DNA free. Next, to obtain a baseline comparison of two DNA collection methods on a non-metallic substrate and identify a suitable number of cells to spot on cartridges, different DNA input amounts of primary human adult epidermal keratinocytes (HEKa) were tested. Thereafter, 300 brass and 300 nickel-plated, cartridges were spotted with HEKa cells containing ~5 ng of DNA, fired or unfired, and processed with either method. Finally, five methods representing hybrids of the soaking and rinse-and-swab methods were tested to determine if variations of those methods could be used to increase DNA yield and recovery. The results show that the soaking method consistently yielded more DNA than the rinse-and-swab method from a non-metallic substrate. However, the comparison study demonstrated that both methods performed comparably for cartridges. On average, the soaking method recovered 0.25 ng of DNA (5.1% recovery) and the rinse-and-swab method recovered 0.28 ng (5.8% recovery). However, average recoveries were significantly different among three analysts and considerable variation in yields were observed, possibly due to storage time. Furthermore, consistent with prior reports, the DNA recovered from brass casings was only 16% of that recovered from nickel-plated casings and the average yield of DNA from fired casings was reduced to 67% of unfired casings. Moreover, DNA extracts from brass or nickel-plated casings did not appear to contain amplification inhibitors and only 30/596 appeared severely degraded. Finally, both the published rinse-and-swab and soaking methods yielded more DNA than all modifications of the two methods. Overall, both methods yielded equivalent DNA quantities. Additionally, recovery of DNA from any given cartridge casing may be dependent on storage time as well as the skill, proficiency, and experience of the analyst and may reflect stochastic effects, particularly for casings containing low copy and/or degraded DNA.
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Affiliation(s)
- Kyleen Elwick
- Visiting Scientist Program, Federal Bureau of Investigation Laboratory Division, Research and Support Unit, 2501 Investigation Parkway, Quantico, VA 22135, USA
| | - Quentin Gauthier
- Visiting Scientist Program, Federal Bureau of Investigation Laboratory Division, Research and Support Unit, 2501 Investigation Parkway, Quantico, VA 22135, USA
| | - Stephanie Rink
- Visiting Scientist Program, Federal Bureau of Investigation Laboratory Division, Research and Support Unit, 2501 Investigation Parkway, Quantico, VA 22135, USA
| | - Emily Cropper
- Visiting Scientist Program, Federal Bureau of Investigation Laboratory Division, Research and Support Unit, 2501 Investigation Parkway, Quantico, VA 22135, USA
| | - Mark F Kavlick
- Federal Bureau of Investigation Laboratory Division, Research and Support Unit, 2501 Investigation Parkway, Quantico, VA 22135, USA.
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11
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Heathfield LJ, Hitewa AN, Gibbon A, Mole CG. The effect of NucleoSpin® Forensic Filters on DNA recovery from trace DNA swabs. Sci Justice 2022; 62:284-287. [PMID: 35598922 DOI: 10.1016/j.scijus.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/27/2022] [Accepted: 03/04/2022] [Indexed: 10/18/2022]
Abstract
Forensic DNA profiling is a globally accepted method for human identification, however, obtaining full DNA profiles from trace DNA can be challenging. The optimal recovery of DNA from trace DNA swabs is therefore crucial. Methods for extracting DNA from swabs often make use of a spin basket combined with a centrifugation step, to enhance the release of cells from the swab prior to DNA extraction. The NucleoSpin® Forensic Filter (Macherey-Nagel, Düren) is a type of spin basket, but it has not been thoroughly assessed on trace DNA samples. This study aimed to assess if the inclusion of the NucleoSpin® Forensic Filter significantly improved DNA recovery and DNA profiling success from cotton and flocked swabs used to collect trace DNA and buccal cells (control). Buccal cells and trace DNA samples were collected from 25 volunteers using each swab type (cotton and flocked) in duplicate. DNA was extracted from the samples using the NucleoSpin® DNA Forensic kit, one set with, and the other set without, NucleoSpin® Forensic Filters. DNA concentration was assessed using real time PCR, and DNA profiling was done using the PowerPlex® ESX 16 system. The inclusion of the NucleoSpin® Forensic Filters significantly improved DNA concentration for buccal cells that were collected using flocked swabs (p = 0.035). However, no significant differences were noted for trace DNA samples for either swab type. There was also no significant difference in DNA profiling success when NucleoSpin® Forensic Filters were used, regardless of swab and sample type. These results may be helpful for laboratories that are considering the NucleoSpin® Forensic Filters in the DNA extraction workflow, particularly for trace DNA samples.
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Affiliation(s)
- Laura Jane Heathfield
- Division of Forensic Medicine and Toxicology, Department of Pathology, Faculty of Health Science, University of Cape Town, South Africa.
| | - Alina Ndahafa Hitewa
- Division of Forensic Medicine and Toxicology, Department of Pathology, Faculty of Health Science, University of Cape Town, South Africa
| | - Andrea Gibbon
- Division of Forensic Medicine and Toxicology, Department of Pathology, Faculty of Health Science, University of Cape Town, South Africa
| | - Calvin Gerald Mole
- Division of Forensic Medicine and Toxicology, Department of Pathology, Faculty of Health Science, University of Cape Town, South Africa
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12
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Chen C, Lin Y, Yu H, Xue Y, Xu Q, Jiang L, Zhu R, Chen A, Yang Y, Xia R, Zhang X, Yang Q, Tao R, Zhu B, Li C, Zhang S. Establishing an integrated pipeline for automatic and efficient detection of trace DNA encountered in forensic applications. Sci Justice 2022; 62:50-59. [PMID: 35033328 DOI: 10.1016/j.scijus.2021.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/13/2021] [Accepted: 10/26/2021] [Indexed: 11/26/2022]
Abstract
The analysis of trace DNA is a crucial component in forensic applications. Biological materials containing low-level DNA collected at crime scenes, such as fingerprints, can be valuable as evidence. Automatic detection of biological samples has been largely embraced in forensic applications to meet the increasing throughput requirements. However, the amount of DNA automatically retrieved from trace evidence often tends to be small and unstable, ultimately resulting in poor detection of DNA profiles. Thus, in this work, we introduced a robust DNA extraction and purification platform named Bionewtech® BN3200 (Bionewtech®, Shanghai, China) with the goal of constructing a rapid automatic detection system for trace DNA. The establishment of automatic detection system for trace DNA mainly encompassed two parts: assessing the sensitivity of automatic extraction platform and screening the optimal short tandem repeat (STR) typing kit. The sensitivity of Bionewtech® BN3200 platform based on Ultra-sensitive DNA Extraction kit was initially estimated, demonstrating that this extraction platform might contain large potential in the trace DNA extraction. For the amplification part, three sets of commercial multiplex STR typing kits were selected as candidates, and the amplified products were further genotyped on the Applied Biosystems 3500xl Genetic Analyzer. After comparation, SiFa™ 23 Plex Kit was determined as the most suitable amplification system for trace DNA. Eventually, the newly exploited trace DNA detection system was successfully implemented in the detection of fingerprints derived from glass surfaces with the five-seconds contact time. As a result, the DNA recovered from the fingerprints fluctuated approximately from 57.60 pg to 18.05 ng, in addition, over 70% of the total STR loci were detected in 75% of the fingerprint samples.
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Affiliation(s)
- Chong Chen
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China; Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China
| | - Yuan Lin
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China
| | - Huan Yu
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Department of Forensic Science, Medical School of Soochow University, Suzhou 215123, China
| | - Yu Xue
- Bionewtech® Company., Ltd., Shanghai 201615, China
| | - Qiannan Xu
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Institute of Forensic Medicine, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China
| | - Lei Jiang
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China
| | - Ruxin Zhu
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China
| | - Anqi Chen
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Department of Forensic Medicine, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yue Yang
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; School of Basic Medicine, Inner Mongolia Medical University, Hohhot 010030, China
| | - Ruocheng Xia
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Department of Forensic Medicine, School of Basic Medical Science, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiaochun Zhang
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Department of Forensic Science, Medical School of Soochow University, Suzhou 215123, China
| | - Qi Yang
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China; Department of Forensic Science, Medical School of Soochow University, Suzhou 215123, China
| | - Ruiyang Tao
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China
| | - Bofeng Zhu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Chengtao Li
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China.
| | - Suhua Zhang
- Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Sciences, Ministry of Justice, Shanghai 200063, China.
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13
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Burrill J, Daniel B, Frascione N. Technical Note: Lysis and purification methods for increased recovery of degraded DNA from touch deposit swabs. Forensic Sci Int 2021; 330:111102. [PMID: 34814081 DOI: 10.1016/j.forsciint.2021.111102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/15/2021] [Accepted: 11/07/2021] [Indexed: 11/04/2022]
Abstract
Touch deposits are a routine yet challenging sample type in forensic casework and research. Recent work investigating their contents has indicated corneocytes to be the major cellular constituent while cell-free DNA is present at significant levels. Prolonged incubation including a reducing agent such as DTT has been shown to lyse corneocytes; a plasma cfDNA recovery kit which targets shorter DNA fragments has been demonstrated to improve cfDNA recovery from hand rinses. Herein these methods are combined and tested on mock casework touch deposit swabs from communal surface areas. Both fluorescence- and qPCR-based quantification methods are used and their results compared to query DNA degradation levels. Both proposed lysis and purification methods demonstrate increased recovery of DNA detectable with fluorescence quantification and some additional alleles at short loci, indicating high levels of fragmented DNA in these samples.
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Affiliation(s)
- Julia Burrill
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, Institute of Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.
| | - Barbara Daniel
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, Institute of Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.
| | - Nunzianda Frascione
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, Institute of Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.
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14
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Jansson L, Swensson M, Gifvars E, Hedell R, Forsberg C, Ansell R, Hedman J. Individual shedder status and the origin of touch DNA. Forensic Sci Int Genet 2021; 56:102626. [PMID: 34781198 DOI: 10.1016/j.fsigen.2021.102626] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022]
Abstract
Due to improved laboratory techniques, touched surfaces and items are increasingly employed as sources of forensic DNA evidence. This has urged a need to better understand the mechanisms of DNA transfer between individuals. Shedder status (i.e. the propensity to leave DNA behind) has been identified as one major factor regulating DNA transfer. It is known that some individuals tend to shed more DNA than others, but the mechanisms behind shedder status are largely unknown. By comparing the amounts of DNA deposited from active hands (i.e. used "as usual") and inactive hands (i.e. not allowed to touch anything), we show that some of the self-DNA deposited from hands is likely to have accumulated on hands from other parts of the body or previously handled items (active hands: 2.1 ± 2.7 ng, inactive hands: 0.83 ± 1.1 ng, paired t-test: p = 0.014, n = 27 pairs of hands). Further investigation showed that individual levels of deposited DNA are highly associated with the level of DNA accumulation on the skin of the face (Pearson's correlation: r = 0.90, p < 0.00001 and Spearman's ranked correlation: rs = 0.56, p = 0.0016, n = 29). We hypothesized that individual differences in sebum secretion levels could influence the amount of DNA accumulation in facial areas, but no such correlation was seen (Pearson's correlation: r = - 0.13, p = 0.66, n = 14). Neither was there any correlation between DNA levels on hands or forehead and the time since hand or face wash. We propose that the amount of self-DNA deposited from hands is highly influenced by the individual levels of accumulated facial DNA, and that cells/DNA is often transferred to hands by touching or rubbing one's face.
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Affiliation(s)
- Linda Jansson
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Marie Swensson
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Emma Gifvars
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Ronny Hedell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden
| | | | - Ricky Ansell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Department of Physics, Chemistry and Biology, IFM, Linköping University, Linköping, Sweden
| | - Johannes Hedman
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
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15
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Burrill J, Hotta R, Daniel B, Frascione N. Accumulation of endogenous and exogenous nucleic acids in "Touch DNA" components on hands. Electrophoresis 2021; 42:1594-1604. [PMID: 34080688 DOI: 10.1002/elps.202000371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/07/2021] [Accepted: 05/20/2021] [Indexed: 02/03/2023]
Abstract
Successful forensic DNA profiling from handled items is increasingly routine in casework. This "touch DNA" is thought to contain both cellular and acellular nucleic acid sources. However, there is little clarity on the origins or characteristics of this material. The cellular component consists of anucleate, terminally differentiated corneocytes (assumed to lack DNA), and the occasional nucleated cell. The acellular DNA source is fragmentary, presumably cell breakdown products. This study examines the relative contributions each component makes to the hand-secretions (endogenous) and hand-accumulations (exogenous) by recovering rinses from the inside and outside of worn gloves. Additionally, cellular and acellular DNA was measured at timepoints up to 2 h after hand washing, both with and without interim contact. Microscopic examination confirmed cell morphology and presence of nucleic acids. Following the novel application of a hair keratinocyte lysis method and plasma-DNA fragment purification to hand rinse samples, DNA profiles were generated from both fractions. Exogenous cell-free DNA is shown to be a significant source of touch DNA, which reaccumulates quickly, although its amplifiable nuclear alleles are limited. Endogenous DNA is mostly cellular in origin and provides more allelic information consistently over time.
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Affiliation(s)
- Julia Burrill
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Rachel Hotta
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Barbara Daniel
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Nunzianda Frascione
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
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16
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How many cells are required for successful DNA profiling? Forensic Sci Int Genet 2021; 51:102453. [PMID: 33422808 DOI: 10.1016/j.fsigen.2020.102453] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/01/2020] [Accepted: 12/06/2020] [Indexed: 02/07/2023]
Abstract
Through advances in fluorescent nucleic acid dye staining and visualisation, targeted collection of cellular material deposited, for example by touch or within a saliva deposit, is possible. In regard to the potential evidentiary value of the deposit the questions remain: 'How many cells are required to generate an informative DNA profile?'; 'How many visualised corneocytes within a touch deposit compared to typical nucleated cells are required in order to achieve successful DNA profiling?'. Diamond TM Nucleic Acid Dye (DD) staining of cellular material, and subsequent visualisation utilising portable fluorescence microscopy, was performed for touch and saliva samples to target defined numbers of cells for collection, by swab and tapelift, and subsequent processing via direct PCR and PCR post-extraction. The resulting DNA quantification data and alleles generated within subsequent DNA profiles could be correlated to the number of cells initially collected to determine cellular threshold requirements for DNA profile generation for each workflow. Full profiles were consistently generated using direct PCR when the template was ≥40 buccal cells collected by either a swab or tapelift. By contrast ≥800 corneocytes collected by swabbing or ≥4,000 corneocytes collected by a tapelift were required to generate same number of STR alleles from touch samples. When samples were processed through a DNA extraction workflow, ≥80 buccal cells were required to generate full profiles from both swab and tapelift, while touch samples required ≥4,000 corneocytes collected by a swab and >8,000 corneocytes collected by a tapelift. The data presented within this study allow for informative sample triage and workflow decisions to be made to optimise STR amplification based on the presence and visual quantification of stained cellular material.
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17
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Yadavalli VK, Ehrhardt CJ. Atomic force microscopy as a biophysical tool for nanoscale forensic investigations. Sci Justice 2020; 61:1-12. [PMID: 33357821 DOI: 10.1016/j.scijus.2020.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/30/2020] [Accepted: 10/04/2020] [Indexed: 01/23/2023]
Abstract
The atomic force microscope (AFM) has found its way to the arsenal of tools available to the forensic practitioner for the analysis of samples at the nano and microscales. As a non-destructive probing tool that requires minimal sample preparation, the AFM is very attractive, particularly in the case of minimal or precious sample. To date, the use of the AFM has primarily been in the arena of imaging where it has been complementary to other microscopic examination tools. Forensic applications in the visual examination of evidence such as blood stains, questioned documents, and hair samples have been reported. While a number of reviews have focused on the use of AFM as an imaging tool for forensic analyses, here we not only discuss these works, but also point to a versatile enhancement in the capabilities of this nanoscale tool - namely its use for force spectroscopy. In this mode, the AFM can determine elastic moduli, adhesion forces, energy dissipation, and the interaction forces between cognate ligands, that can be spatially mapped to provide a unique spatial visualization of properties. Our goals in this review are to provide a context for this capability of the AFM, explain its workings, cover some exemplary works pertaining to forensic sciences, and present a critical analysis on the advantages and disadvantages of this modality. Equipped with this high-resolution tool, imaging and biophysical analysis by the AFM can provide a unique complement to other tools available to the researcher for the analysis and characterization of forensic evidence.
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Affiliation(s)
- Vamsi K Yadavalli
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Christopher J Ehrhardt
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA 23284, USA
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18
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Burrill J, Rammenou E, Alawar F, Daniel B, Frascione N. Corneocyte lysis and fragmented DNA considerations for the cellular component of forensic touch DNA. Forensic Sci Int Genet 2020; 51:102428. [PMID: 33338861 DOI: 10.1016/j.fsigen.2020.102428] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/30/2020] [Accepted: 11/12/2020] [Indexed: 01/28/2023]
Abstract
DNA deposited by individuals' hands is a routine part of forensic analysis, yet little is understood about the precise cellular contents left by handling. "Dead" skin cells known as corneocytes make up the majority of the cellular material left in touch deposits by people's hands but are known to lack nuclei, making their DNA content ambiguous. Here we measure DNA released from anucleate corneocytes following various lysis methods to determine how much DNA may be present in these cells and how best to recover it from inside the cornified envelope. We demonstrate that enhanced lysis methods using a reducing agent and longer incubation may be valuable for hand deposit samples. Corneocyte DNA can be characterized as highly degraded based on the quantification, STR profiling and fluorescence microscopy of the cells from freshly washed hands. Purification to target shorter DNA fragments is demonstrated. DNA from the washed corneocyte cells is shown to constitute the majority of recoverable DNA with these methods. We consider the use of new methods adapted to cornified cells and fragmented DNA for future research into this sample type.
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Affiliation(s)
- Julia Burrill
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, London, United Kingdom.
| | - Elli Rammenou
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, London, United Kingdom.
| | - Fatima Alawar
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, London, United Kingdom.
| | - Barbara Daniel
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, London, United Kingdom.
| | - Nunzianda Frascione
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, London, United Kingdom.
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19
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Exploration of cell-free DNA (cfDNA) recovery for touch deposits. Forensic Sci Int Genet 2020; 51:102431. [PMID: 33260058 DOI: 10.1016/j.fsigen.2020.102431] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/15/2022]
Abstract
Although touch deposit DNA is widely used in forensic casework, its cellular and acellular contents and their biological origins are poorly understood. There is evidence that the cell-free component of DNA deposited by handling may contribute substantial genetic information; however, most research into touch DNA recovery does not separate cellular and cell-free fractions or seek to characterize their contents. This work is an important early step in developing methods to isolate the cfDNA from biological material deposited by handling. Size-filtration as a separation technique was determined to be prone to DNA loss, even on optimized control samples of pure ladder DNA. Centrifugal separation was optimized to determine minimum speed and time required to reliably remove all cellular debris from the material collected by rinsing donor hands. To determine if the centrifugal force risked rupturing shed corneocyte cells and releasing cellular DNA into the supernatant, DNA levels were measured, and cells were visualized microscopically before and after centrifugation of hand rinses. Heated buccal cells were used as a positive control to demonstrate cell rupture would be detected with these methods. Following the determination of a suitable separation technique, an investigation into purification methods for cfDNA was conducted. DNA recovery using three kits for plasma cfDNA, one for PCR clean-up and one for genomic DNA were assessed on both ladder DNA to simulate cfDNA fragments and on collected hand deposit supernatants from both unwashed and washed hands. Purification methods designed for recovery of short DNA fragments from plasma yielded the highest recovery percentage across sample types, with BioChain cfPure performing the best. Donors' hands were shown to shed high levels of cfDNA, which were better recovered with a method for short fragments than with a traditional genomic technique often used on touch DNA samples.
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20
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Miller M, Philpott MK, Olsen A, Tootham M, Yadavalli VK, Ehrhardt CJ. Technical note: Survey of extracellular and cell-pellet-associated DNA from 'touch'/trace samples. Forensic Sci Int 2020; 318:110557. [PMID: 33168421 DOI: 10.1016/j.forsciint.2020.110557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/02/2020] [Accepted: 10/16/2020] [Indexed: 01/26/2023]
Abstract
The goal of this study was to characterize the reproducibility of extracellular and cell pellet associated DNA yields recovered from handled substrates. Results showed that extracellular DNA yields were extremely variable between contributors-ranging between 0 and >10ng-and tended to dwarf cell pellet yields, which varied between 0 and ∼230pg. DNA yields across multiple samples from the same contributor on different days showed similar levels of variability in both DNA fractions, indicating that extracellular DNA yield is largely influenced by extrinsic and/or environmental factors and is not a contributor-specific attribute. Microscopic surveys of cells from the pellet fraction as well as fingerprints from the same contributor samples were conducted following treatment with fluorescent DNA stain. Nearly all imaged cells exhibited diffuse fluorescence across the cell without discernable evidence of nuclei. This is consistent with the limited nature of DNA recovery from the pellet fraction and the prevalence of extracellular DNA in these samples.
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Affiliation(s)
- Mekhi Miller
- Department of Forensic Science, Virginia Commonwealth University, Richmond VA, United States
| | - M Katherine Philpott
- Department of Forensic Science, Virginia Commonwealth University, Richmond VA, United States
| | - Anita Olsen
- Department of Chemical and Life Sciences Engineering, Virginia Commonwealth University, Richmond, VA, United States
| | - Mary Tootham
- Department of Forensic Science, Virginia Commonwealth University, Richmond VA, United States
| | - Vamsi K Yadavalli
- Department of Chemical and Life Sciences Engineering, Virginia Commonwealth University, Richmond, VA, United States
| | - Christopher J Ehrhardt
- Department of Forensic Science, Virginia Commonwealth University, Richmond VA, United States.
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21
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Schulte KQ, Hewitt FC, Manley TE, Reed AJ, Baniasad M, Albright NC, Powals ME, LeSassier DS, Smith AR, Zhang L, Allen LW, Ludolph BC, Weber KL, Woerner AE, Freitas MA, Gardner MW. Fractionation of DNA and protein from individual latent fingerprints for forensic analysis. Forensic Sci Int Genet 2020; 50:102405. [PMID: 33152624 DOI: 10.1016/j.fsigen.2020.102405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 08/13/2020] [Accepted: 10/03/2020] [Indexed: 01/03/2023]
Abstract
Human touch samples represent a significant portion of forensic DNA casework. Yet, the generally low abundance of genetic material combined with the predominantly extracellular nature of DNA in these samples makes DNA-based forensic analysis exceptionally challenging. Human proteins present in these same touch samples offer an abundant and environmentally-robust alternative. Proteogenomic methods, using protein sequence variants arising from nonsynonymous DNA mutations, have recently been applied to forensic analysis and may represent a viable option looking forward. However, DNA analysis remains the gold standard and any proteomics-based methods would need to consider how DNA could be co-extracted from samples without significant loss. Herein, we describe a simple workflow for the collection, enrichment and fractionation of DNA and protein in latent fingerprint samples. This approach ensures that DNA collected from a latent fingerprint can be analyzed by traditional DNA casework methods, while protein can be proteolytically digested and analyzed via standard liquid chromatography-tandem mass spectrometry-based proteomics methods from the same touch sample. Sample collection from non-porous surfaces (i.e., glass) is performed through the application of an anionic surfactant over the fingermark. The sample is then split into separate DNA and protein fractions following centrifugation to enrich the protein fraction by pelleting skin cells. The results indicate that this workflow permits analysis of DNA within the sample, yet highlights the challenge posed by the trace nature of DNA in touch samples and the potential for DNA to degrade over time. Protein deposited in touch samples does not appear to share this limitation, with robust protein quantities collected across multiple human donors. The quantity and quality of protein remains robust regardless of fingerprint age. The proteomic content of these samples is consistent across individual donors and fingerprint age, supporting the future application of genetically variable peptide (GVP) analysis of touch samples for forensic identification.
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Affiliation(s)
| | | | | | - Andrew J Reed
- Mass Spectrometry and Proteomics Facility, Campus Chemistry Instrument Center, The Ohio State University, Columbus, OH, USA
| | - Maryam Baniasad
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | | | | | | | | | - Liwen Zhang
- Mass Spectrometry and Proteomics Facility, Campus Chemistry Instrument Center, The Ohio State University, Columbus, OH, USA
| | | | | | | | - August E Woerner
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Michael A Freitas
- Mass Spectrometry and Proteomics Facility, Campus Chemistry Instrument Center, The Ohio State University, Columbus, OH, USA; The Ohio State University Wexner Medical Center, Columbus, OH, USA
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22
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Forensic touch DNA recovery from metal surfaces – A review. Sci Justice 2020; 60:206-215. [DOI: 10.1016/j.scijus.2020.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/20/2020] [Accepted: 01/26/2020] [Indexed: 12/23/2022]
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23
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Burrill J, Daniel B, Frascione N. Illuminating touch deposits through cellular characterization of hand rinses and body fluids with nucleic acid fluorescence. Forensic Sci Int Genet 2020; 46:102269. [PMID: 32155589 DOI: 10.1016/j.fsigen.2020.102269] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 02/20/2020] [Accepted: 02/29/2020] [Indexed: 12/23/2022]
Abstract
Forensic DNA typing from touched or handled items in routine casework is increasing as the sensitivity of detection techniques improves. Our understanding of the cellular/acellular content of touch deposits and the origins of the DNA therein is still limited. This work explores the cellular content of rinses from washed and unwashed hands, as well as saliva, nasal and eye washes which could be sources of transferred DNA onto hands. Flow cytometry and microscopic examination were used to detect granularity, size and nucleic acid fluorescence data. Cellular content did not vary significantly within an individual, although some differences were observed between donors. Saliva contained populations of nucleated epithelia as well as smaller cells and debris, all positive for DNA. Hand rinses consisted almost entirely of anucleate corneocytes, many of which also stained positive for nucleic acids. These data raise questions about shed corneocyte DNA content previously assumed to be negligible.
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Affiliation(s)
- Julia Burrill
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, Franklin-Wilkins Building, 4.122, 150 Stamford Street, London SE1 9NH, United Kingdom.
| | - Barbara Daniel
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, Franklin-Wilkins Building, 4.122, 150 Stamford Street, London SE1 9NH, United Kingdom.
| | - Nunzianda Frascione
- King's Forensics, Department of Analytical, Environmental & Forensic Sciences, School of Population Health & Environmental Sciences, King's College London, Franklin-Wilkins Building, 4.122, 150 Stamford Street, London SE1 9NH, United Kingdom.
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24
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Dierig L, Schmidt M, Wiegand P. Looking for the pinpoint: Optimizing identification, recovery and DNA extraction of micro traces in forensic casework. Forensic Sci Int Genet 2020; 44:102191. [DOI: 10.1016/j.fsigen.2019.102191] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/08/2019] [Accepted: 10/17/2019] [Indexed: 12/17/2022]
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25
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Romero-García C, Rosell-Herrera R, Revilla C, Baeza-Richer C, Gomes C, Palomo-Díez S, Arroyo-Pardo E, López-Parra A. Effect of the activity in secondary transfer of DNA profiles. FORENSIC SCIENCE INTERNATIONAL GENETICS SUPPLEMENT SERIES 2019. [DOI: 10.1016/j.fsigss.2019.10.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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26
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LeSassier DS, Schulte KQ, Manley TE, Smith AR, Powals ML, Albright NC, Ludolph BC, Weber KL, Woerner AE, Gardner MW, Hewitt FC. Artificial fingerprints for cross-comparison of forensic DNA and protein recovery methods. PLoS One 2019; 14:e0223170. [PMID: 31581206 PMCID: PMC6776342 DOI: 10.1371/journal.pone.0223170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/20/2019] [Indexed: 11/18/2022] Open
Abstract
Quantitative genomic and proteomic evaluation of human latent fingerprint depositions represents a challenge within the forensic field, due to the high variability in the amount of DNA and protein initially deposited. To better assess recovery techniques for touch depositions, we present a method to produce simple and customizable artificial fingerprints. These artificial fingerprint samples include the primary components of a typical latent fingerprint, specifically sebaceous fluid, eccrine perspiration, extracellular DNA, and proteinaceous epidermal skin material (i.e., shed skin cells). A commercially available emulsion of sebaceous and eccrine perspiration material provides a chemically-relevant suspension solution for fingerprint deposition, simplifying artificial fingerprint production. Extracted human genomic DNA is added to accurately mimic the extracellular DNA content of a typical latent print and comparable DNA yields are recovered from the artificial prints relative to human prints across surface types. Capitalizing on recent advancements in the use of protein sequence identification for human forensic analysis, these samples also contain a representative quantity of protein, originating from epidermal skin cells collected from the fingers and palms of volunteers. Proteomic sequencing by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis indicates a high level of protein overlap between artificial and latent prints. Data are available via ProteomeXchange with identifier PXD015445. By including known quantities of DNA and protein into each artificial print, this method enables total DNA and protein recovery to be quantitatively assessed across different sample collection and extraction methods to better evaluate extraction efficiency. Collectively, these artificial fingerprint samples are simple to make, highly versatile and customizable, and accurately represent the biochemical composition and biological signatures of human fingerprints.
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Affiliation(s)
| | | | - Tara E. Manley
- Signature Science, LLC, Austin, Texas, United States of America
| | - Alan R. Smith
- Signature Science, LLC, Austin, Texas, United States of America
| | - Megan L. Powals
- Signature Science, LLC, Austin, Texas, United States of America
| | | | | | | | - August E. Woerner
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
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27
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Brazilian forensic casework analysis through MPS applications: Statistical weight-of-evidence and biological nature of criminal samples as an influence factor in quality metrics. Forensic Sci Int 2019; 303:109938. [DOI: 10.1016/j.forsciint.2019.109938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 08/22/2019] [Indexed: 12/18/2022]
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28
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Borja T, Karim N, Goecker Z, Salemi M, Phinney B, Naeem M, Rice R, Parker G. Proteomic genotyping of fingermark donors with genetically variant peptides. Forensic Sci Int Genet 2019; 42:21-30. [DOI: 10.1016/j.fsigen.2019.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/09/2019] [Accepted: 05/26/2019] [Indexed: 01/31/2023]
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29
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Sessa F, Salerno M, Bertozzi G, Messina G, Ricci P, Ledda C, Rapisarda V, Cantatore S, Turillazzi E, Pomara C. Touch DNA: impact of handling time on touch deposit and evaluation of different recovery techniques: An experimental study. Sci Rep 2019; 9:9542. [PMID: 31267029 PMCID: PMC6606590 DOI: 10.1038/s41598-019-46051-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 06/17/2019] [Indexed: 12/22/2022] Open
Abstract
"Touch DNA" is DNA obtained from biological material transferred from a donor to an object or a person during physical contact. This particular kind of evidence could play an essential role in forensic laboratory work and is considered an important tool for investigators. Even though the principal aspects of "Touch DNA" have been extensively studied, to date, there are few reports in the research field of DNA retrieval from garments that have been worn. This study aimed to investigate the "handling time", analyzing particularly the minimum contact time required to deposit a sufficient amount of DNA on a garment to produce an interpretable profile of the "handler". Moreover, three different sampling techniques were compared ("dry swab", "cutting out", and "adhesive tape") with the aim of defining the technique that guarantees the best recovery of the three methods tested. Analyzing the data of this experimental model, a "handling time" of two seconds is enough to release sufficient DNA on to a garment to obtain a complete profile. Moreover, this study demonstrated that when targeting for foreign DNA, the sample area should be narrowed down as much as possible to the smallest area possible to maximize target DNA recovery.
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Affiliation(s)
- Francesco Sessa
- Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy.
| | - Monica Salerno
- Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy
| | - Giuseppe Bertozzi
- Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Pietrantonio Ricci
- Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy.,Institute of Legal Medicine, Università degli Studi Magna Graecia di Catanzaro, Catanzaro, Italy
| | - Caterina Ledda
- Department "G.F. Ingrassia" - Section of Hygiene and Public Health, University of Catania, Catania, Italy
| | - Venerando Rapisarda
- Department "G.F. Ingrassia" - Section of Hygiene and Public Health, University of Catania, Catania, Italy
| | - Santina Cantatore
- Department of Clinical and Experimental Medicine, Section of Legal Medicine, University of Foggia, Foggia, Italy
| | | | - Cristoforo Pomara
- Department of Medical and Surgical Sciences and Advanced Technologies GF Ingrassia, University of Catania, Catania, Italy.
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Comte J, Baechler S, Gervaix J, Lock E, Milon MP, Delémont O, Castella V. Touch DNA collection - Performance of four different swabs. Forensic Sci Int Genet 2019; 43:102113. [PMID: 31525724 DOI: 10.1016/j.fsigen.2019.06.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/18/2019] [Accepted: 06/18/2019] [Indexed: 12/28/2022]
Abstract
A collaborative study conducted by three police forensic units, a DNA laboratory, and a forensic academic institute was undertaken in order to compare the performance of four different swabs in controlled and quasi-operational conditions. For this purpose, a reference swab (Prionics cardboard evidence collection kit) currently used within the police forensic units and 3 challenger swabs (COPAN 4N6FLOQSwabs™ (Genetics variety), Puritan FAB-MINI-AP and Sarstedt Forensic Swab) were used for collecting DNA traces from previously used items (referred as "touch DNA" in this article) including on 60 collars, 60 screwdrivers and 60 steering wheels obtained from volunteers. For each comparison, the surface considered was divided into two equal components; one was sampled with the reference swab and the other with one of the three challenger swabs. This lead to a total of 360 samples. Conclusions were consistent within the four operational partners. From a practical point of view, the COPAN 4N6FLOQSwabs™ (Genetics variety) was judged the most convenient to use. Furthermore, it allowed the recovery of significantly more DNA from collars (0.65 vs 0.13 ng/μL) and steering wheels (2.82 vs 1.77 ng/μL), and a similar amount of DNA from screwdrivers (0.032 vs 0.026 ng/μL) compared with the Prionics reference swab. The two other challenger swabs provided results that were not significantly different from the reference swab, except for the Puritan swab, whose performance was significantly lower for steering wheels (0.37 vs 0.58 ng/μL). As part of a conservation study, 50 μL of a blood dilution (1/4 with PBS) was deposited on a total of 105 COPAN (Genetics and Crime Scene varieties), Prionics and Sarstedt swabs. They were stored within a cupboard at room temperature. The integrity of the recovered DNA was evaluated with NGM SElect™ DNA profiles after different time-spans ranging from 1 day to 12 months by comparing the height difference of the peaks occurring at the shortest and longest loci, respectively. DNA seemed to remain stable, except when using the COPAN 4N6FLOQSwabs™ treated with an antimicrobial agent (Crime scene variety), which resulted in significant DNA degradation. Following these tests, the COPAN 4N6FLOQSwabs™ (Genetics variety), a model with a desiccant, was selected for further testing in fully operational conditions.
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Affiliation(s)
- Jennifer Comte
- Unité de Génétique Forensique, Centre Universitaire Romand de Médecine Légale, Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Ch. de la Vulliette 4, 1000 Lausanne 25, Switzerland
| | - Simon Baechler
- Service forensique, Police neuchâteloise, Rue des Poudrières 14, 2006 Neuchâtel, Switzerland; Ecole des Sciences Criminelles, Université de Lausanne, UNIL-Batochime, 1015 Lausanne, Switzerland; Laboratoire de Recherche en Criminalistique, Université du Québec à Trois-Rivières, 3351 Bd des Forges, Trois-Rivières G8Z 4M3, Canada
| | - Joelle Gervaix
- Unité de Génétique Forensique, Centre Universitaire Romand de Médecine Légale, Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Ch. de la Vulliette 4, 1000 Lausanne 25, Switzerland
| | - Eric Lock
- Departement de la sécurité et de l'économie, Police judiciaire, Section Forensique, Bd Carl-Vogt 17-19, 1205 Genève, Switzerland
| | - Marie-Pierre Milon
- Police de Sûreté, Brigade de police scientifique, Route de la Blécherette 101, 1014 Lausanne, Switzerland
| | - Olivier Delémont
- Ecole des Sciences Criminelles, Université de Lausanne, UNIL-Batochime, 1015 Lausanne, Switzerland
| | - Vincent Castella
- Unité de Génétique Forensique, Centre Universitaire Romand de Médecine Légale, Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Ch. de la Vulliette 4, 1000 Lausanne 25, Switzerland.
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31
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Sterling S, Mason KE, Anex DS, Parker GJ, Hart B, Prinz M. Combined
DNA
Typing and Protein Identification from Unfired Brass Cartridges,,,. J Forensic Sci 2019; 64:1475-1481. [DOI: 10.1111/1556-4029.14042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/15/2019] [Accepted: 02/15/2019] [Indexed: 12/25/2022]
Affiliation(s)
| | - Katelyn E. Mason
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | - Deon S. Anex
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | | | - Bradley Hart
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | - Mechthild Prinz
- John Jay College of Criminal Justice 524 W. 59th St. New York NY 10019
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32
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A review of trace “Touch DNA” deposits: Variability factors and an exploration of cellular composition. Forensic Sci Int Genet 2019; 39:8-18. [DOI: 10.1016/j.fsigen.2018.11.019] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 11/14/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023]
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Gosch A, Courts C. On DNA transfer: The lack and difficulty of systematic research and how to do it better. Forensic Sci Int Genet 2019; 40:24-36. [PMID: 30731249 DOI: 10.1016/j.fsigen.2019.01.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/21/2018] [Accepted: 01/30/2019] [Indexed: 01/07/2023]
Abstract
Since DNA from touched items and surfaces ("touch DNA") can successfully and reliably be analyzed, the question as to how a particular DNA containing sample came to be from where it was recovered is of increasing forensic interest and expert witnesses in court are increasingly challenged to assess for instance whether an incriminatory DNA sample matching to a suspect could have been transferred to the crime scene in an innocent manner and to guess at the probability of such an occurrence. The latter however will frequently entail expressing a subjective probability i.e. simply making a best guess from experience. There is, to the present date, an extensive and complex body of literature on primary, secondary, tertiary and even higher order DNA transfer, its possibility, plausibility, dependency on an array of variables and factors and vast numbers of permutations thereof. However, from our point of view there is a lack of systematic data on DNA transfer with existing research widely varying in quality and relevance. Our aim was, starting from a comprehensive survey of the status quo and appreciating its increasing importance, to in the first part of our review raise consciousness towards the underestimated and insufficiently accounted for complexity of DNA transfer and thus appendant research of forensic scientists serving as expert witnesses in court but also acting in the role of a journal referee to point them to areas of criticism when reviewing a manuscript on DNA transfer. In the second part, we present propositions how to systematize and integrate future research efforts concerning DNA transfer. Also, we present a searchable database providing an extensive overview of the current state of knowledge on DNA transfer, intended to facilitate the identification of relevant studies adding knowledge to a specific question and thus help forensic experts to base their opinion on a broader, more complete and more reproducible selection of studies.
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Affiliation(s)
- Annica Gosch
- Institute of Forensic Medicine, University Hospital of Schleswig-Holstein, Arnold-Heller-Strasse 12, 24105 Kiel, Germany
| | - Cornelius Courts
- Institute of Forensic Medicine, University Hospital of Schleswig-Holstein, Arnold-Heller-Strasse 12, 24105 Kiel, Germany.
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Wang C, Stanciu CE, Ehrhardt CJ, Yadavalli VK. Nanoscale characterization of forensically relevant epithelial cells and surface associated extracellular DNA. Forensic Sci Int 2017; 277:252-258. [PMID: 28672218 DOI: 10.1016/j.forsciint.2017.06.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/18/2017] [Accepted: 06/18/2017] [Indexed: 01/03/2023]
Abstract
Atomic force microscopy provides a novel morphological and physico-chemical perspective to analyze epithelial cell samples in forensic investigations. As a nanoscale, single cell tool, it allows the investigation of scarce samples in a non-destructive fashion. Using chemical force spectroscopy, it permits the identification of specific functional groups or surface molecules. Of specific interest is the presence of extracellular DNA (eDNA) on the surface of epithelial cells that line the exterior skin and interior cavities of human bodies, and can transfer onto surfaces through contact with skin and saliva. To date, this eDNA has only been measured a bulk level. Here, using nanoscale imaging, we first describe the unique differences between keratinized epithelial cells and non-keratinized buccal cells. Then via a force mapping technique, we show how eDNA can be spatially located and quantified on the cell surface. Our results suggest that presence and relative quantity of surface-associated, extracellular DNA signatures can be analyzed on individual epithelial cells from different tissue sources, providing a new tool in the forensic analysis of touch samples.
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Affiliation(s)
- Congzhou Wang
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Cristina E Stanciu
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | | | - Vamsi K Yadavalli
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA.
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35
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Analysis of cellular autofluorescence in touch samples by flow cytometry: implications for front end separation of trace mixture evidence. Anal Bioanal Chem 2017; 409:4167-4179. [PMID: 28516277 PMCID: PMC5486938 DOI: 10.1007/s00216-017-0364-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 04/12/2017] [Indexed: 12/20/2022]
Abstract
The goal of this study was to survey optical and biochemical variation in cell populations deposited onto a surface through touch or contact and identify specific features that may be used to distinguish and then sort cell populations from separate contributors in a trace biological mixture. Although we were not able to detect meaningful biochemical variation in touch samples deposited by different contributors through preliminary antibody surveys, we did observe distinct differences in red autofluorescence emissions (650-670 nm), with as much as a tenfold difference in mean fluorescence intensities observed between certain pairs of donors. Results indicate that the level of red autofluorescence in touch samples can be influenced by a donor's contact with specific material prior to handling the substrate from which cells were collected. In particular, we observed increased red autofluorescence in cells deposited subsequent to handling laboratory gloves, plant material, and certain types of marker ink, which could be easily visualized microscopically or using flow cytometry, and persisted after hand washing. To test whether these observed optical differences could potentially be used as the basis for a cell separation workflow, a controlled two-person touch mixture was separated into two fractions via fluorescence-activated cell sorting (FACS) using gating criteria based on intensity of 650-670 nm emissions and then subjected to DNA analysis. Genetic analysis of the sorted fractions provided partial DNA profiles that were consistent with separation of individual contributors from the mixture suggesting that variation in autofluorescence signatures, even if driven by extrinsic factors, may nonetheless be a useful means of isolating contributors to some touch mixtures. Graphical Abstract Conceptual workflow diagram. Trace biological mixtures containing cells from multiple individuals are analyzed by flow cytometry. Cells are then physically separated into two populations based on intensity of red autofluorescence using Fluorescence Activated Cell Sorting. Each isolated cell fraction is subjected to DNA analysis resulting in a DNA profile for each contributor.
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36
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Stanciu CE, Philpott MK, Bustamante EE, Kwon YJ, Ehrhardt CJ. Analysis of red autofluorescence (650-670nm) in epidermal cell populations and its potential for distinguishing contributors to 'touch' biological samples. F1000Res 2016; 5:180. [PMID: 27990254 PMCID: PMC5130068 DOI: 10.12688/f1000research.8036.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/11/2016] [Indexed: 11/29/2022] Open
Abstract
Interpretation of touch DNA mixtures poses a significant challenge for forensic caseworking laboratories. Front end techniques that facilitate separation of contributor cell populations before DNA extraction are a way to circumvent this problem. The goal of this study was to survey intrinsic fluorescence of epidermal cells collected from touch surfaces and investigate whether this property could potentially be used to discriminate between contributor cell populations in a biological mixture. Analysis of red autofluorescence (650-670nm) showed that some contributors could be distinguished on this basis. Variation was also observed between autofluorescence profiles of epidermal cell populations from a single contributor sampled on different days. This dataset suggests that red autofluorescence may be a useful marker for identifying distinct cell populations in some mixtures. Future efforts should continue to investigate the extrinsic or intrinsic factors contributing to this signature, and to identify additional biomarkers that could complement this system.
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Affiliation(s)
- Cristina E Stanciu
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - M Katherine Philpott
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Eduardo E Bustamante
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Ye Jin Kwon
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
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