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Madden I, Taylor D, Mitchell N, Goray M, Henry J. Predicting probative levels of touch DNA on tapelifts using Diamond™ Nucleic Acid Dye. Forensic Sci Int Genet 2024; 70:103024. [PMID: 38335775 DOI: 10.1016/j.fsigen.2024.103024] [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: 08/22/2023] [Revised: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024]
Abstract
Tapelifting is a common strategy to recover touch DNA deposits from porous exhibits in forensic DNA casework. However, it is known that only about 30 % of tapelifts submitted for DNA analysis in operational forensic laboratories yield profiles suitable for comparison or upload to a searchable database. A reliable means to identify and remove non-probative tapelifts from the workflow would reduce sample backlogs and provide significant cost savings. We investigated whether the amount of macroscopic or microscopic fluorescence on a tapelift following staining with Diamond Nucleic Acid Dye (DD), determined using a Polilight and Dino Lite microscope respectively, could predict the DNA yield and/or the DNA profiling outcome using controlled (saliva), semi-controlled (finger mark) and uncontrolled (clothing) samples. Both macroscopic and microscopic DD fluorescence could predict DNA yield and profiling outcome for all sample types, however the predictive power deteriorated as the samples became less controlled. For tapelifts of clothing, which are operationally relevant, Polilight fluorescence scores were significantly impacted by clothing fibres and other non-cellular debris and could not be used to identify non-probative samples. The presence of less than 500 cells on a clothing tapelift using microscopic counting of stained corneocytes was identified as a potential threshold for a non-probative DNA profiling outcome. A broader examination of the reliability of this threshold using a casework trial is recommended. Due to the labour intensiveness of microscopic cell counting, and the increased risk of inadvertent contamination, automation of this process using image software in conjunction with artificial neural networks (ANN) should be explored.
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Affiliation(s)
- Isla Madden
- College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia 5042, Australia
| | - Duncan Taylor
- College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia 5042, Australia; Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia
| | - Natasha Mitchell
- Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia
| | - Mariya Goray
- College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia 5042, Australia
| | - Julianne Henry
- College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia 5042, Australia; Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia.
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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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van Oorschot RAH, Meakin GE, Kokshoorn B, Goray M, Szkuta B. DNA Transfer in Forensic Science: Recent Progress towards Meeting Challenges. Genes (Basel) 2021; 12:genes12111766. [PMID: 34828372 PMCID: PMC8618004 DOI: 10.3390/genes12111766] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/04/2021] [Accepted: 11/04/2021] [Indexed: 01/16/2023] Open
Abstract
Understanding the factors that may impact the transfer, persistence, prevalence and recovery of DNA (DNA-TPPR), and the availability of data to assign probabilities to DNA quantities and profile types being obtained given particular scenarios and circumstances, is paramount when performing, and giving guidance on, evaluations of DNA findings given activity level propositions (activity level evaluations). In late 2018 and early 2019, three major reviews were published on aspects of DNA-TPPR, with each advocating the need for further research and other actions to support the conduct of DNA-related activity level evaluations. Here, we look at how challenges are being met, primarily by providing a synopsis of DNA-TPPR-related articles published since the conduct of these reviews and briefly exploring some of the actions taken by industry stakeholders towards addressing identified gaps. Much has been carried out in recent years, and efforts continue, to meet the challenges to continually improve the capacity of forensic experts to provide the guidance sought by the judiciary with respect to the transfer of DNA.
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Affiliation(s)
- Roland A. H. van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC 3085, Australia
- School of Molecular Sciences, La Trobe University, Bundoora, VIC 3086, Australia
- Correspondence:
| | - Georgina E. Meakin
- Centre for Forensic Science, University of Technology Sydney, Ultimo, NSW 2007, Australia;
- Centre for the Forensic Sciences, Department of Security and Crime Science, University College London, London WC1H 9EZ, UK
| | - Bas Kokshoorn
- Netherlands Forensic Institute, 2497 GB The Hague, The Netherlands;
- Faculty of Technology, Amsterdam University of Applied Sciences, 1097 DZ Amsterdam, The Netherlands
| | - Mariya Goray
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia;
| | - Bianca Szkuta
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia;
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Cook R, Mitchell N, Henry J. Assessment of Diamond™ Nucleic Acid Dye for the identification and targeted sampling of latent DNA in operational casework. Forensic Sci Int Genet 2021; 55:102579. [PMID: 34455366 DOI: 10.1016/j.fsigen.2021.102579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/04/2021] [Accepted: 08/15/2021] [Indexed: 12/19/2022]
Abstract
Recovery and DNA profiling of latent touch DNA deposits is a ubiquitous practice by operational forensic laboratories that provides critical evidence in many criminal investigations. Despite recent improvements in the sensitivity of contemporary DNA profiling kits, the inability to localise and visually quantify touch DNA deposits on an exhibit means that ineffective or unwarranted sampling is often performed leading to poor success. Diamond™ Nucleic Acid Dye (DD) is a fluorescent DNA binding dye which has recently been shown to bind to corneocytes enabling visualisation and targeted sampling of touch DNA deposits under controlled conditions. The ability to translate these findings to operational casework, where a diverse range of substrates is encountered and the amount and distribution of touch DNA is uncontrolled, is currently unknown. Here, we provide the first report on the use of DD in an operational context. Spraying items with DD was shown to have no impact on downstream immunological testing, DNA extraction, or DNA profiling with the GlobalFiler™ PCR amplification kit. DD was shown to effectively locate areas of touch DNA on select exhibits using the Polilight. Issues with background fluorescence, non-specific staining, interference from fingerprint enhancement reagents, or absorbance of the excitation light by black surfaces demonstrated that DD is not compatible with all exhibits. Background fluorescence also prevented the use of DD to screen for the presence of cellular material on IsoHelix swabs post-sampling but it was suitable for screening Lovell DNA tapelifts. A casework trial of 49 plastic bag and tape exhibits showed limited application of DD to triage out negative items as DNA was recovered from items where DD fluorescence was not detected. Where DD fluorescence was detected, its broad distribution prevented targeted sampling and any correlation to be made between the amount observed and DNA yield or profiling outcome. The DD procedure also increased the time taken to search exhibits and risk of inadvertent contamination. Our study suggests that DD is not suited as a generalised screening technique across all touch casework exhibits but further investigation is warranted to determine its applicability to specific exhibit types.
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Affiliation(s)
- Russell Cook
- Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia
| | - Natasha Mitchell
- Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia
| | - Julianne Henry
- Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia; College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia 5042, Australia.
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Shedder status: Exploring means of determination. Sci Justice 2021; 61:391-400. [DOI: 10.1016/j.scijus.2021.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 01/29/2023]
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Schmidt M, Bamberg M, Dierig L, Kunz SN, Wiegand P. The diversity of shedder tests and a novel factor that affects DNA transfer. Int J Legal Med 2021; 135:1267-1280. [PMID: 33783604 DOI: 10.1007/s00414-021-02533-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/10/2021] [Indexed: 01/27/2023]
Abstract
Since the first shedder test was formulated almost 20 years ago, a plethora of different test strategies has emerged. The amount of data generated so far is considerable. However, because of the limited reproducibility of its results, the reliability of the shedder concept is frequently questioned. This study provides a literature overview of applied shedder tests that capture the diversity of the concept. It is pointed out to what extent different classification criteria, workflows, and trace evaluation can impair the classification outcome. The robustness of shedder status was assessed by applying a promising approach established by Fonneløp et al. (Forensic Sci Int Genet 29:48-60, 21). Data provide similar results to those in recent studies but also ambiguous shedder classifications. The applied shedder test was adapted based on our own as well as the reviewed data. With novel classification parameters, promising results were achieved. This study reveals uncertainties and inconsistencies of the shedder concept. Recommendations for harmonization and transparency are proposed. Implementation of the recommendations may result in an increased impact on casework and transfer studies, including activity-level assessments. Furthermore, this study shows that moisturizers affect participants' shedder status as well as DNA transfer. The impact appears to remain relevant even 60 min post ointment application but depends greatly on the type of moisturizer applied.
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Affiliation(s)
- Max Schmidt
- Institute of Legal Medicine, University Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany.
| | - Malte Bamberg
- Institute of Legal Medicine, University Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Lisa Dierig
- Institute of Legal Medicine, University Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Sebastian N Kunz
- Institute of Legal Medicine, University Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Peter Wiegand
- Institute of Legal Medicine, University Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany
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Champion J, Kanokwongnuwut P, van Oorschot RAH, Taylor D, Linacre A. Evaluation of a fluorescent dye to visualize touch DNA on various substrates. J Forensic Sci 2021; 66:1435-1442. [PMID: 33629435 DOI: 10.1111/1556-4029.14695] [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: 12/13/2020] [Revised: 01/29/2021] [Accepted: 02/08/2021] [Indexed: 11/29/2022]
Abstract
A wide variety of items are submitted as evidence in a forensic investigation. Identifying the location of DNA on such items is central to maximizing DNA profiling success and thus the ability to link a person of interest to a particular item or crime. Recent publications describe a fluorescent staining method using Diamond™ Dye (DD) to visualize cellular material on the surface of non-porous items (e.g., glass, plastic). However, substrates of varying porosity and background color have not yet been examined. Varying porous substrates (i.e., paper bank note, stamp, cigarette, wooden matchstick, and fabric) and non-porous substrates (i.e., enamel tooth and plastic bank note) were examined for their suitability with the use of DD. To improve the visualization of cellular material on the porous substrates, we also explored two DD diluents and adjusting image contrast. The results suggest the optimal diluent depends on the absorbent nature of the substrate. For example, ethanol was sufficient for visualization on the non-porous substrates, whereas water was better for the porous substrates. While cellular material was detected on the paper bank note, tooth, and stamp, background fluorescence or autofluorescence and surface type of matchstick prevented clear visualization on this substrate. It was also determined that by adjusting the contrast of images for tooth, paper bank note and matchstick aided in the detection of cellular material. Overall, this study extends the use of DD for latent DNA detection to absorbent substrates, highlights the limitations associated with these substrate types, and suggests modifications to improve visualization on these challenging substrates.
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Affiliation(s)
- Jessica Champion
- College of Science & Engineering, Flinders University, Adelaide, SA, Australia
| | | | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Vic., Australia.,School of Molecular Sciences, La Trobe University, Bundoora, Vic., Australia
| | - Duncan Taylor
- College of Science & Engineering, Flinders University, Adelaide, SA, Australia.,Forensic Science South Australia, Adelaide, SA, Australia
| | - Adrian Linacre
- College of Science & Engineering, Flinders University, Adelaide, SA, Australia
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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: 14] [Impact Index Per Article: 4.7] [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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Kanokwongnuwut P, Paul Kirkbride K, Linacre A. An assessment of tape-lifts. Forensic Sci Int Genet 2020; 47:102292. [DOI: 10.1016/j.fsigen.2020.102292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 01/30/2023]
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10
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Olsen A, Miller M, Yadavalli VK, Ehrhardt CJ. Open source software tool for the automated detection and characterization of epithelial cells from trace biological samples. Forensic Sci Int 2020; 312:110300. [PMID: 32371282 DOI: 10.1016/j.forsciint.2020.110300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 11/25/2022]
Abstract
This paper presents a strategy for an unsupervised workflow for identifying epithelial cells in microscopic images and characterizing their morphological and/or optical properties. The proposed method can be used on cells that have been stained with fluorescent dyes and imaged using conventional optical microscopes. The workflow was tested on cell populations that were imaged directly on touch/contact surfaces and stained with nucleic acid dyes to visualize genetic content. Our results show that this approach could be a useful strategy for characterizing differences in staining efficiency and/or morphological properties of individual cells or aggregate populations within a biological sample. Further, they can potentially reduce the laborious nature of microscopic analysis and increase throughput and reproducibility of similar studies.
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Affiliation(s)
- Anita Olsen
- Department of Chemical and Life Sciences Engineering, Virginia Commonwealth University, Richmond, VA, United States
| | - Mekhi Miller
- 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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