1
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Flanagan L, Murphy C, Savage P, Breathnach M, Ryan J. The importance of male underwear in cases of alleged sexual assault. J Forensic Sci 2024; 69:1481-1489. [PMID: 38703136 DOI: 10.1111/1556-4029.15539] [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: 12/15/2023] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/06/2024]
Abstract
The potential evidential value of male underwear in cases of alleged sexual assault is often overlooked. Male underwear can be a critical item in the investigation of alleged sexual assaults. Body fluids/DNA, which may transfer to the penis during sexual contact, may in turn transfer to the inside front of the underwear, and persist for months or years, provided the underwear are not washed. Here, we demonstrate how the case circumstances drive the sampling strategy of male underwear, in order to maximize the effectiveness of the forensic analysis. Sampling considerations including recovery methods and sampling sequence are discussed, and a methodical examination strategy of male underwear is proposed. To highlight the pertinence of male underwear to the investigation of alleged sexual assaults, three real-life cases are discussed, in which male underwear were examined for multiple body fluids/DNA, and the findings obtained proved evidentially significant. The different cases demonstrate the versatility of male underwear examination in situations, where different body fluids and DNA may transfer based on the specific allegation, and emphasize how targeted sampling can allow the scientist to assess the probability of the findings based on two competing propositions. Accurate sampling strategies are imperative for robust probability assignment in evaluative reporting of scientific findings.
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Affiliation(s)
- Lorna Flanagan
- Forensic Science Ireland, Backweston Laboratory Campus, Celbridge, County Kildare, Ireland
| | - Charlotte Murphy
- Forensic Science Ireland, Backweston Laboratory Campus, Celbridge, County Kildare, Ireland
| | - Paula Savage
- Forensic Science Ireland, Backweston Laboratory Campus, Celbridge, County Kildare, Ireland
| | - Michelle Breathnach
- Forensic Science Ireland, Backweston Laboratory Campus, Celbridge, County Kildare, Ireland
| | - Jennifer Ryan
- Forensic Science Ireland, Backweston Laboratory Campus, Celbridge, County Kildare, Ireland
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2
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Petcharoen P, Nolan M, Kirkbride KP, Linacre A. Shedding more light on shedders. Forensic Sci Int Genet 2024; 72:103065. [PMID: 38851033 DOI: 10.1016/j.fsigen.2024.103065] [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: 02/22/2024] [Revised: 04/15/2024] [Accepted: 05/26/2024] [Indexed: 06/10/2024]
Abstract
We report on testing 100 individuals for their shedder status with the aim of demonstrating whether the process of cell staining is reproducible when testing a large number of people. A previous report using the same method was based on 11 donors and indicated that there may be a continuum of shedder types within this small sample set. In this report we also expand the time points post-handwashing to 0, 15, 30, 60, and 180 min. Triplicate samples were collected from both the right and left thumbs. Samples were collected by donors placing a thumb on a clean glass slide and then adding a DNA binding dye. The number of cells were recorded within three separate square millimetre areas (cells/mm2) at 220x magnification. The experiments were conducted in triplicate on three different days, giving a total of 72 thumbprints per individual. Finally, there were 3438 observed frames in the entire dataset. Of the 100 donors, 98 gave consistent and reproducible cell number deposition. There was no difference between the cells deposited by the left and right thumbs in 13 of 15 tested. Males tended to deposit more cells than females. If applying arbitrary boundary to a cell count to definitively determine shedder status, then many of the donors fell within two categories. This study based on 100 individuals strongly suggests that shedder status is a continuum phenomenon.
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Affiliation(s)
- Piyamas Petcharoen
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Madison Nolan
- College of Science & Engineering, Flinders University, Adelaide 5042, Australia
| | - K Paul Kirkbride
- College of Science & Engineering, Flinders University, Adelaide 5042, Australia
| | - Adrian Linacre
- College of Science & Engineering, Flinders University, Adelaide 5042, Australia.
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3
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Hughes DA, van Oorschot RAH, Szkuta B, Conlan XA. The effect of the anti-coagulant EDTA on the deposition and adhesion of whole blood deposits on non-porous substrates. J Forensic Sci 2024; 69:1061-1068. [PMID: 38415957 DOI: 10.1111/1556-4029.15483] [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: 10/24/2023] [Revised: 01/19/2024] [Accepted: 01/26/2024] [Indexed: 02/29/2024]
Abstract
An investigation into whether the addition of a commonly used anti-coagulant agent like ethylenediaminetetraacetic acid (EDTA) has an impact on the adhesion potential of blood to non-porous substrates was conducted. Two non-porous substrates (aluminum and polypropylene) exhibiting six different surface roughness categories (R1-R6) were used as test substrates upon which either whole blood or blood treated with EDTA was deposited. Samples were exposed to different drying periods (24 hours, 48 hours, and 1 week) before undergoing a tapping agitation experiment in order to evaluate the adhesion to the surface. Clear differences in adhesion potential were observed between whole blood and blood treated with EDTA. Blood treated with EDTA displayed a stronger adhesion strength to aluminum after a drying time of 24 h pre-agitation, while whole blood presented with a stronger adhesion strength at the drying time of 48 h and 1 week. Both EDTA-treated and EDTA-untreated blood was shown to dislodge less easily on polypropylene with the only difference observed on smooth surfaces (0.51-1.50 μm surface roughness). Thus, when conducting transfer studies using smooth hydrophobic substrates like polypropylene or considering the likelihood of transfer given specific case scenarios, differences in adhesion strength of blood due to hydrophobic substrate characteristics and a decreased surface area need to be considered. Overall, whole blood displayed a better adhesion strength to aluminum, emphasizing that indirect transfer probability experiments using EDTA blood on substrates like aluminum should take an increased dislodgment tendency into account in their transfer estimations.
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Affiliation(s)
- Deborah A Hughes
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, Macleod, Victoria, Australia
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, Macleod, Victoria, Australia
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia
| | - Bianca Szkuta
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| | - Xavier A Conlan
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
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4
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Prinz M, Pirtle D, Oldoni F. Global survey on evaluative reporting on DNA evidence with regard to activity-level propositions. J Forensic Sci 2024; 69:798-813. [PMID: 38351537 DOI: 10.1111/1556-4029.15488] [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: 10/21/2023] [Revised: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 04/26/2024]
Abstract
For many criminal cases, the source of who deposited the DNA is not what the prosecutor and the defense are trying to dispute. In court, the question may be how the DNA was deposited at the crime scene rather than who the DNA came from. Although laboratories in many countries have begun to evaluate DNA evidence given formal activity-level propositions (ALPs), it is unknown how much other forensic practitioners know and what they think about activity-level evaluative reporting (ALR). To collect this information, a survey with 21 questions was submitted to international forensic science organizations across Europe, Australia, South America, Canada, Asia, and Africa. The survey combined open-ended and multiple-choice questions and received 162 responses. Responses revealed a wide range of knowledge on the topic. Overall, most respondents were somewhat knowledgeable about ALR, ALP, and current practices in court and expressed their support of the concept. A majority of participants identified gaps and obstacles regarding ALR they would like to see addressed. Examples include (1) need for more education/training at all stakeholder levels, (2) need for more DNA evidence-related data under realistic case scenarios, (3) need to internally implement and validate a formalized and objective approach for reporting, and (4) in some countries the need to achieve court admissibility. This global survey gathered the current concerns of forensic DNA practitioners and outlined several operational concerns. The information can be used to advance the implementation of ALR in laboratories and court testimony worldwide.
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Affiliation(s)
- Mechthild Prinz
- John Jay College of Criminal Justice, New York, New York, USA
| | - Devyn Pirtle
- John Jay College of Criminal Justice, New York, New York, USA
| | - Fabio Oldoni
- Department of Chemistry & Physics, Arcadia University, Glenside, Pennsylvania, USA
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5
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Goray M, Taylor D, Bibbo E, Fantinato C, Fonneløp AE, Gill P, van Oorschot RAH. Emerging use of air eDNA and its application to forensic investigations - A review. Electrophoresis 2024; 45:916-932. [PMID: 38419135 DOI: 10.1002/elps.202300228] [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: 10/11/2023] [Revised: 12/17/2023] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
Biological material is routinely collected at crime scenes and from exhibits and is a key type of evidence during criminal investigations. Improvements in DNA technologies allow collection and profiling of trace samples, comprised of few cells, significantly expanding the types of exhibits targeted for DNA analysis to include touched surfaces. However, success rates from trace and touch DNA samples tend to be poorer compared to other biological materials such as blood. Simultaneously, there have been recent advances in the utility of environmental DNA collection (eDNA) in identification and tracking of different biological organisms and species from bacteria to naked mole rats in different environments, including, soil, ice, snow, air and aquatic. This paper examines the emerging methods and research into eDNA collection, with a special emphasis on the potential forensic applications of human DNA collection from air including challenges and further studies required to progress implementation.
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Affiliation(s)
- Mariya Goray
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Duncan Taylor
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Forensic Science SA, Adelaide, South Australia, Australia
| | - Emily Bibbo
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Chiara Fantinato
- Forensic Genetics Research Group, Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ane Elida Fonneløp
- Forensic Genetics Research Group, Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Peter Gill
- Forensic Genetics Research Group, Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Roland A H van Oorschot
- Victoria Police Forensic Services Department, Office of Chief Forensic Scientist, Macleod, Victoria, Australia
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia
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6
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Lee LYC, Lee YS, Tan J, Lee JY, Syn CKC. A study of DNA transfers onto plastic packets placed in personal bags. J Forensic Sci 2024; 69:430-436. [PMID: 38288847 DOI: 10.1111/1556-4029.15460] [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: 09/19/2023] [Revised: 11/06/2023] [Accepted: 01/03/2024] [Indexed: 03/07/2024]
Abstract
The ability to detect low level DNA brings with it the uncertainty of whether the detected DNA is a result of transfer. To address this uncertainty, a simulation study was conducted in which a mock illicit drug packet was placed into the personal bags of individuals. When the average transit time of the packets was increased from around 2 h to more than 14 h, the percentage of the DNA profiles recovered from the packets which could be attributed to the individuals increased greatly from 5.3% to 48.6%. We found that drug packers who were poor shedders could not be included as contributors to the DNA profiles from the drug packets at all and there was a higher chance that individuals other than themselves could be included as contributors to the DNA profile recovered from drug packets. We also found that it was equally likely that the drug packers who had direct contact with the drug packets and bag owners who did not, could be included as contributors to the DNA profiles recovered from the packets. The results in this study highlight the importance of taking into consideration the transit time of drug packet, the shedder status of the alleged packer and the history of an item, when evaluating DNA evidence in the context of illicit drug activities.
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Affiliation(s)
- Li Yen Candy Lee
- DNA Profiling Laboratory, Biology Division, Health Sciences Authority, Singapore, Singapore
| | - Yong Sheng Lee
- DNA Profiling Laboratory, Biology Division, Health Sciences Authority, Singapore, Singapore
| | - Jiayu Tan
- DNA Profiling Laboratory, Biology Division, Health Sciences Authority, Singapore, Singapore
| | - Jun Yu Lee
- DNA Profiling Laboratory, Biology Division, Health Sciences Authority, Singapore, Singapore
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7
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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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8
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Onofri M, Tommolini F, Severini S, Gambelunghe C, Lancia M, Carlini L, Carnevali E. Trace DNA Transfer in Co-Working Spaces: The Importance of Background DNA Analysis. Int J Mol Sci 2024; 25:2207. [PMID: 38396883 PMCID: PMC10888653 DOI: 10.3390/ijms25042207] [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: 12/15/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
The presence of background DNA (bgDNA) can hinder the evaluation of DNA evidence at the activity level, especially when the suspect is expected to be retrieved due to their habitual occupation of the investigated environment. Based on real-life casework circumstances, this study investigates the prevalence, composition, origin, and probable transfer routes of bgDNA found on personal items in situations where their owner and person of interest (POI) share the same workspace. Baseline values of bgDNA were evaluated on the participants' personal items. Secondary and higher degree transfer scenarios of non-self DNA deposition were also investigated. The DNA from co-workers and co-inhabiting partners can be recovered from an individual's personal belongings. Non-self DNA present on the hands and deposited on a sterile surface can generate uninformative profiles. The accumulation of foreign DNA on surfaces over time appears to be crucial for the recovery of comparable profiles, resulting in detectable further transfer onto other surfaces. For a thorough evaluation of touch DNA traces at the activity level, it is necessary to collect information not only about DNA transfer probabilities but also about the presence of the POI as part of the 'baseline' bgDNA of the substrates involved.
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Affiliation(s)
- Martina Onofri
- Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy; (F.T.); (S.S.); (E.C.)
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy; (C.G.); (M.L.); (L.C.)
| | - Federica Tommolini
- Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy; (F.T.); (S.S.); (E.C.)
| | - Simona Severini
- Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy; (F.T.); (S.S.); (E.C.)
| | - Cristiana Gambelunghe
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy; (C.G.); (M.L.); (L.C.)
| | - Massimo Lancia
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy; (C.G.); (M.L.); (L.C.)
| | - Luigi Carlini
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy; (C.G.); (M.L.); (L.C.)
| | - Eugenia Carnevali
- Forensic Sciences Laboratory, Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy; (F.T.); (S.S.); (E.C.)
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9
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Sessa F, Pomara C, Esposito M, Grassi P, Cocimano G, Salerno M. Indirect DNA Transfer and Forensic Implications: A Literature Review. Genes (Basel) 2023; 14:2153. [PMID: 38136975 PMCID: PMC10742555 DOI: 10.3390/genes14122153] [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: 10/05/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Progress in DNA profiling techniques has made it possible to detect even the minimum amount of DNA at a crime scene (i.e., a complete DNA profile can be produced using as little as 100 pg of DNA, equivalent to only 15-20 human cells), leading to new defense strategies. While the evidence of a DNA trace is seldom challenged in court by a defendant's legal team, concerns are often raised about how the DNA was transferred to the location of the crime. This review aims to provide an up-to-date overview of the experimental work carried out focusing on indirect DNA transfer, analyzing each selected paper, the experimental method, the sampling technique, the extraction protocol, and the main results. Scopus and Web of Science databases were used as the search engines, including 49 papers. Based on the results of this review, one of the factors that influence secondary transfer is the amount of DNA shed by different individuals. Another factor is the type and duration of contact between individuals or objects (generally, more intimate or prolonged contact results in more DNA transfer). A third factor is the nature and quality of the DNA source. However, there are exceptions and variations depending on individual characteristics and environmental conditions. Considering that secondary transfer depends on multiple factors that interact with each other in unpredictable ways, it should be considered a complex and dynamic phenomenon that can affect forensic investigation in various ways, for example, placing a subject at a crime scene who has never been there. Correct methods and protocols are required to detect and prevent secondary transfer from compromising forensic evidence, as well as the correct interpretation through Bayesian networks. In this context, the definition of well-designed experimental studies combined with the use of new forensic techniques could improve our knowledge in this challenging field, reinforcing the value of DNA evidence in criminal trials.
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Affiliation(s)
- Francesco Sessa
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
| | - Cristoforo Pomara
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
| | | | - Patrizia Grassi
- “Vittorio Emanuele” Hospital, University of Catania, 95121 Catania, Italy;
| | - Giuseppe Cocimano
- Department of Mental and Physical Health and Preventive Medicine, University of Campania “Vanvitelli”, 80121 Napoli, Italy;
| | - Monica Salerno
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
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10
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Oefelein R, Cresswell S, Matheson C, Jean-Louis T. Overall Proportion of Total DNA Consistent with an Individual Briefly Handling a Firearm. Genes (Basel) 2023; 14:2127. [PMID: 38136949 PMCID: PMC10743288 DOI: 10.3390/genes14122127] [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: 10/17/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
In forensic investigations, DNA profiles are routinely obtained from firearms evidence and alternative hypotheses may be proposed for consideration on the activity level. DNA profiles found to be consistent with the DNA profile of a specific individual could be a result of directly handling the firearm or other modes of transfer of DNA. Sixteen law-enforcement-owned firearms were evaluated with samples collected from the frame and slide area, the trigger and trigger guard area, and the front and rear sights after brief handling by laboratory personnel. Twenty-two out of forty-eight samples resulted in DNA profiles suitable for comparison, of which six resulted in likelihood ratios (LR) that demonstrated support for the hypothesis that included the brief handler as a contributor to the DNA profile obtained from the sample. Five of these samples were obtained from the frame and slide and one was from the trigger and trigger guard area. None of the DNA profiles obtained from the sights supported the inclusion of the brief handler as a contributor to the DNA profile. Gaining knowledge and supporting data on the nature of DNA profiles typically obtained from both owners and brief handlers can be useful for the purposes of evaluative reporting when considering results obtained from firearm evidence.
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Affiliation(s)
- Rachel Oefelein
- DNA Labs International, Deerfield Beach, FL 33441, USA; (R.O.); (T.J.-L.)
- School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia;
| | - Sarah Cresswell
- School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia;
| | - Carney Matheson
- School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia;
| | - Tania Jean-Louis
- DNA Labs International, Deerfield Beach, FL 33441, USA; (R.O.); (T.J.-L.)
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11
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Fantinato C, Fonneløp AE, Bleka Ø, Vigeland MD, Gill P. The invisible witness: air and dust as DNA evidence of human occupancy in indoor premises. Sci Rep 2023; 13:19059. [PMID: 37925517 PMCID: PMC10625553 DOI: 10.1038/s41598-023-46151-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023] Open
Abstract
Humans constantly shed deoxyribonucleic acid (DNA) into the surrounding environment. This DNA may either remain suspended in the air or it settles onto surfaces as indoor dust. In this study, we explored the potential use of human DNA recovered from air and dust to investigate crimes where there are no visible traces available-for example, from a recently vacated drugs factory where multiple workers had been present. Samples were collected from three indoor locations (offices, meeting rooms and laboratories) characterized by different occupancy types and cleaning regimes. The resultant DNA profiles were compared with the reference profiles of 55 occupants of the premises. Our findings showed that indoor dust samples are rich sources of DNA and provide an historical record of occupants within the specific locality of collection. Detectable levels of DNA were also observed in air and dust samples from ultra-clean forensic laboratories which can potentially contaminate casework samples. We provide a Bayesian statistical model to estimate the minimum number of dust samples needed to detect all inhabitants of a location. The results of this study suggest that air and dust could become novel sources of DNA evidence to identify current and past occupants of a crime scene.
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Affiliation(s)
- Chiara Fantinato
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway.
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Ane Elida Fonneløp
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Øyvind Bleka
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
| | | | - Peter Gill
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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12
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Monkman H, Szkuta B, van Oorschot RAH. Presence of Human DNA on Household Dogs and Its Bi-Directional Transfer. Genes (Basel) 2023; 14:1486. [PMID: 37510390 PMCID: PMC10379355 DOI: 10.3390/genes14071486] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/11/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Awareness of the factors surrounding the transfer of DNA from a person, item, or surface to another person, item, or surface is highly relevant during investigations of alleged criminal activity. Animals in domestic environments could be a victim, offender, or innocent party associated with a crime. There is, however, very limited knowledge of human DNA transfer, persistence, prevalence, and recovery (DNA TPPR) associated with domestic animals. This pilot study aimed to improve our understanding of DNA TPPR associated with domestic dogs by collecting and analysing samples from various external areas of dogs of various breeds, interactions with humans, and living arrangements, and conducting a series of tests to investigate the possibility of dogs being vectors for the indirect transfer of human DNA. Reference DNA profiles from the dog owners and others living in the same residence were acquired to assist interpretation of the findings. The findings show that human DNA is prevalent on dogs, and in the majority of samples, two-person mixtures are present. Dogs were also found to be vectors for the transfer of human DNA, with DNA transferred from the dog to a gloved hand during patting and a sheet while walking.
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Affiliation(s)
- Heidi Monkman
- School of Life and Environmental Sciences, Deakin University, Geelong 3220, Australia
- College of Science and Engineering, Flinders University, Bedford Park 5042, Australia
| | - Bianca Szkuta
- School of Life and Environmental Sciences, Deakin University, Geelong 3220, Australia
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod 3085, Australia
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora 3086, Australia
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13
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Taylor A, Davidson G, Boyce M, Murphy C, Doole S, Rogers C, Fraser I. Background levels of body fluids and DNA on the shaft of the penis and associated underpants in the absence of sexual activity. Sci Justice 2023; 63:529-536. [PMID: 37453785 DOI: 10.1016/j.scijus.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/18/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023]
Abstract
This study examines the background of blood, saliva, semen and autosomal DNA on penile swabs and underpants from males in the absence of recent sexual activity. Based on the data collected by the AFSP Body Fluid Forum, the results of this study show that; there is a very low expectation of detecting blood on penile swabs and male underpants; a low expectation of detecting saliva on penile swabs and male underpants; and spermatozoa would be expected in less than a quarter of penile swabs and three quarters of male underpants. As none of the samples had detectable levels of DNA which were suitable for meaningful comparison that did not match the donor or their partner, the expectation of detecting a DNA profile from the cellular background on penile swabs or underpants from a male who has not been involved in recent sexual intercourse is very low. The results of this study are extremely informative when evaluating the significance of blood, saliva, semen and DNA detected on the penile swabs and underpants of males in cases of alleged sexual assault.
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Affiliation(s)
- A Taylor
- Formerly of Forensic Science Northern Ireland, 151 Belfast Road, Carrickfergus, Co. Antrim BT38 8PL, Northern Ireland
| | - G Davidson
- Cellmark Forensic Services, Buckshaw Link, Ordnance Road, Buckshaw Village, Chorley, Lancashire PR7 7EL, United Kingdom.
| | - M Boyce
- Formerly of Key Forensic Services, 207C Cavendish Place, Birchwood Park, Warrington WA3 6WU, United Kingdom
| | - C Murphy
- Department of Justice and Equality, Forensic Science Ireland, Garda Headquarters, Phoenix Park, Dublin 8, Ireland.
| | - S Doole
- Eurofins Forensic Services, Sir Alec Jeffreys Building, Peel Avenue, Calderpark, Wakefield WF2 7UA, United Kingdom.
| | - C Rogers
- SPA Forensic Services, Scottish Crime Campus, Craignethan Drive, Gartcosh G69 8AE. United Kingdom.
| | - I Fraser
- Forensic Science Northern Ireland, 151 Belfast Road, Carrickfergus, Co. Antrim BT38 8PL, Northern Ireland.
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14
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Aalbers SE, Khan AT, Weir BS. Perceptions of forensic scientists on statistical models, sequence data, and ethical implications for DNA evidence evaluations: A qualitative assessment. Forensic Sci Int Synerg 2023; 6:100335. [PMID: 37325613 PMCID: PMC10265457 DOI: 10.1016/j.fsisyn.2023.100335] [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: 02/23/2023] [Revised: 04/30/2023] [Accepted: 05/09/2023] [Indexed: 06/17/2023]
Abstract
With the introduction of next generation sequencing (NGS) technology in the forensic field, it will be of interest to assess if forensic scientists feel equipped to interpret and present DNA evidence for sequence data. Here, we describe perceptions of sixteen U.S.-based forensic scientists on statistical models, sequence data, and ethical implications for DNA evidence evaluations. To get an in-depth understanding of the current situation, we used a qualitative research approach with a cross-sectional study design. Semi-structured interviews (N = 16) were conducted with U.S. forensic scientists working with DNA evidence. Open-ended interview questions were used to explore participants' views and needs surrounding the use of statistical models and sequence data for forensic purposes. We conducted a conventional content analysis using ATLAS. ti software and employed a second coder to ensure reliability of our results. Eleven themes emerged: 1) a statistical model that maximizes the value of the evidence is preferred; 2) a high-level understanding of the statistical model used is generally sufficient; 3) transparency is key in minimizing the risk of creating black boxes; 4) training and education should be an ongoing effort; 5) the effectiveness of presenting results in court can be improved; 6) NGS has the potential to become revolutionary; 7) some hesitations surrounding the use of sequence data remain; 8) there is a need for a concrete plan to alleviate barriers to the implementation of sequencing techniques; 9) ethics plays a major part in the role of a forensic scientist; 10) ethical barriers for sequence data depend on the application; 11) DNA evidence has its limitations. The results of this study give insight into the perceptions of forensic scientists regarding the use of statistical models and sequence data, providing valuable information in the move towards implementing sequencing methods for DNA evidence evaluations.
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Affiliation(s)
- Sanne E. Aalbers
- Institute for Public Health Genetics, University of Washington, Seattle, WA, USA
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Alyna T. Khan
- Institute for Public Health Genetics, University of Washington, Seattle, WA, USA
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Bruce S. Weir
- Institute for Public Health Genetics, University of Washington, Seattle, WA, USA
- Department of Biostatistics, University of Washington, Seattle, WA, USA
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15
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Ohta J, Minegishi S, Noda N, Sakurada K. Estimating the way of deposition of saliva stains using quantitative analysis of forensic salivary biomarkers. Leg Med (Tokyo) 2023; 64:102277. [PMID: 37300921 DOI: 10.1016/j.legalmed.2023.102277] [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: 04/14/2023] [Revised: 05/19/2023] [Accepted: 05/28/2023] [Indexed: 06/12/2023]
Abstract
Analyzing the way of deposition of saliva stains contributes to appropriate interpretation of saliva as evidence in court, particularly in sexual assault cases. In this proof-of-concept study, we aimed to confirm the difference between drooling-derived (non-contact) saliva and licking-derived (contact) saliva and clarify whether objectively distinguishing between the two saliva is possible. To allow discrimination between these two samples, an indicator was devised where the relative Streptococcus salivarius DNA quantity was calculated by dividing the S. salivarius DNA copies by the amount of stained saliva from the same saliva sample using quantitative polymerase chain reaction and salivary α-amylase activity assays. The study findings reveal that the value of the proposed indicator of licking-derived saliva was 100-fold significantly greater than that of drooling-derived saliva (P < 0.05, Welch's t-test). However, theoretical and technical challenges preclude the application of this indicator as a practical method. We believe that this saliva-specific bacterial DNA-based approach could allow estimation of the saliva stain deposition method.
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Affiliation(s)
- Jun Ohta
- Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Forensic Biology Unit, Scientific Crime Laboratory, Kanagawa Prefectural Police, 155-1 Yamashita-cho, Naka-ku, Yokohama, Kanagawa 231-0023, Japan.
| | - Saki Minegishi
- Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Nanaka Noda
- Forensic Biology Unit, Scientific Crime Laboratory, Kanagawa Prefectural Police, 155-1 Yamashita-cho, Naka-ku, Yokohama, Kanagawa 231-0023, Japan
| | - Koichi Sakurada
- Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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16
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Reither JB, van Oorschot RAH, Durdle A, Szkuta B. DNA transfer to placed, stored, and handled drug packaging and knives in houses. Forensic Sci Int Genet 2023; 65:102888. [PMID: 37182457 DOI: 10.1016/j.fsigen.2023.102888] [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: 11/22/2022] [Revised: 05/04/2023] [Accepted: 05/07/2023] [Indexed: 05/16/2023]
Abstract
Forensic laboratories often sample weapons and clip-seal plastic bags (CSPB) used to package illicit material for the purpose of identifying the handler(s). However, there may be other explanations as to how a person's DNA was transferred to such items. This may include an individual storing the item among their personal belongings for somebody else or the item being stored among their belongings without their knowledge. Here we investigate the direct transfer of DNA to knives and CSPB during handling and explore two feasible alternative explanations related to the indirect transfer of DNA to these items in residential environments. The handling of DNA-free items was performed by 10 individuals who were instructed, on separate occasions, to cut a foam board in half and fill a CSPB with a drug substitute. To explore indirect transfer, sets of these items were (a) placed on kitchen benches and coffee/dining tables for ∼1 min, or (b) stored for two days in kitchen and bedroom drawers within the homes of 10 individuals. After each of the three scenarios, samples were collected from the knife handle and blade, the body and seal of the CSPB, and the surface the items were placed on, the latter as a measure to gain insight into the presence of prevalent and/or background DNA. DNA transfer was observed under all three scenarios, though more frequently when items were handled or stored for 2 days, compared to when placed on a surface for ∼1 min. Under the latter scenario, DNA, if present, was below the level of detection in many samples and produced no profile, suggesting that detectable DNA transfer occurs to a lesser degree from static brief contacts. The study results and associated probabilities will assist forensic examiners with their interpretation of case circumstances regarding the transfer and recovery of DNA from these items.
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Affiliation(s)
- Jack B Reither
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia; Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC 3085, Australia.
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC 3085, Australia; School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia
| | - Annalisa Durdle
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia
| | - Bianca Szkuta
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia
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17
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Onofri M, Altomare C, Severini S, Tommolini F, Lancia M, Carlini L, Gambelunghe C, Carnevali E. Direct and Secondary Transfer of Touch DNA on a Credit Card: Evidence Evaluation Given Activity Level Propositions and Application of Bayesian Networks. Genes (Basel) 2023; 14:genes14050996. [PMID: 37239356 DOI: 10.3390/genes14050996] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
In a judiciary setting, questions regarding the mechanisms of transfer, persistence, and recovery of DNA are increasingly more common. The forensic expert is now asked to evaluate the strength of DNA trace evidence at activity level, thus assessing if a trace, given its qualitative and quantitative features, could be the result of an alleged activity. The present study is the reproduction of a real-life casework scenario of illicit credit card use by a co-worker (POI) of its owner (O). After assessing the shedding propensity of the participants, differences in DNA traces' qualitative and quantitative characteristics, given scenarios of primary and secondary transfer of touch DNA on a credit card, a non-porous plastic support, were investigated. A case-specific Bayesian Network to aid statistical evaluation was created and discrete observations, meaning the presence/absence of POI as a major contributor in both traces from direct and secondary transfer, were used to inform the probabilities of disputed activity events. Likelihood Ratios at activity level (LRα) were calculated for each possible outcome resulting from the DNA analysis. In instances where only POI and POI plus an unknown individual are retrieved, the values obtained show moderate to low support in favour of the prosecution proposition.
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Affiliation(s)
- Martina Onofri
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
| | - Cristina Altomare
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
| | - Simona Severini
- Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy
| | - Federica Tommolini
- Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy
| | - Massimo Lancia
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
| | - Luigi Carlini
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
| | - Cristiana Gambelunghe
- Section of Legal Medicine, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
| | - Eugenia Carnevali
- Section of Legal Medicine, Department of Medicine and Surgery, Santa Maria Hospital, University of Perugia, 05100 Terni, Italy
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18
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Carrara L, Hicks T, Samie L, Taroni F, Castella V. DNA transfer when using gloves in burglary simulations. Forensic Sci Int Genet 2023; 63:102823. [PMID: 36563530 DOI: 10.1016/j.fsigen.2022.102823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/21/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Several studies have demonstrated that DNA can be indirectly transferred from an individual onto a surface. Therefore, the presence of DNA that is compatible with a given person does not necessarily mean that this person has touched the surface on which the DNA was recovered. The present work simulates cases, where DNA is recovered on a door handle and compared to several reference DNA profiles. The DNA profile of the trace shares DNA components with a person of interest (POI). When asked about the DNA results, the POI says he has nothing to do with the incident and has never been at the scene. However, a possibility would be that the DNA came from his recently stolen gloves. Someone else, the alternative offender (AO), could have opened the door wearing his gloves (POI's gloves), and transferred his DNA (POI's DNA). Based on the above-mentioned scenario, 60 burglary simulations experiments were carried out to generate data to assess DNA results given these allegations. The quantity and quality of DNA profiles (NGM SElect) recovered when the POI opened/closed the door bare-handed or when someone else performed the same activity but using POI's gloves, were compared. The gloves were regularly worn during at least three months by their owner during the winter. On the contrary, the AO wore them only for two minutes. Among the traces collected on the door handles, less than 50% of the traces led to interpretable DNA profiles. In 30% of the cases (3/10), when the door was opened/closed with bare hands, the DNA found on the door handle led to a mixed DNA profile with the POI's DNA aligning with the major contributor. For the experiments where the AO opened/closed the door with the POI's gloves, the POI's DNA was compatible with 22% (11/50) of the mixed DNA profile, aligning with the major in 8% of the cases (4/50). The DNA profiles of the offices' occupants were observed on the door handles, but not the AO's. In addition to the results of the experiments, we show two examples of how one can assess results observed in casework. Given the possibility of indirect transfer of minute DNA quantities, this research emphasizes the need to evaluate DNA results given the activities when the POI has a legitimate reason that can explain the presence of their DNA.
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Affiliation(s)
- L Carrara
- School of Criminal Justice, Faculty of Law, Criminal Justice and Public Administration, University of Lausanne, Batochime, 1015 Lausanne, Switzerland.
| | - T Hicks
- Fondation pour la Formation Continue Universitaire Lausannoise (UNIL-EPFL) & School of Criminal Justice, Batochime, Dorigny, 1015 Lausanne, Switzerland; Forensic Genetics Unit, University Center of Legal Medicine, Lausanne-Geneva, Lausanne University Hospital and University of Lausanne, Lausanne 100025, Switzerland
| | - L Samie
- Forensic Genetics Unit, University Center of Legal Medicine, Lausanne-Geneva, Lausanne University Hospital and University of Lausanne, Lausanne 100025, Switzerland
| | - F Taroni
- School of Criminal Justice, Faculty of Law, Criminal Justice and Public Administration, University of Lausanne, Batochime, 1015 Lausanne, Switzerland
| | - V Castella
- Forensic Genetics Unit, University Center of Legal Medicine, Lausanne-Geneva, Lausanne University Hospital and University of Lausanne, Lausanne 100025, Switzerland
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19
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Thompson WC. Uncertainty in probabilistic genotyping of low template DNA: A case study comparing STRMix™ and TrueAllele™. J Forensic Sci 2023; 68:1049-1063. [PMID: 36847295 DOI: 10.1111/1556-4029.15225] [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: 10/15/2022] [Revised: 01/27/2023] [Accepted: 02/02/2023] [Indexed: 03/01/2023]
Abstract
Two probabilistic genotyping (PG) programs, STRMix™ and TrueAllele™, were used to assess the strength of the same item of DNA evidence in a federal criminal case, with strikingly different results. For STRMix, the reported likelihood ratio in favor of the non-contributor hypothesis was 24; for TrueAllele it ranged from 1.2 million to 16.7 million, depending on the reference population. This case report seeks to explain why the two programs produced different results and to consider what the difference tells us about the reliability and trustworthiness of these programs. It uses a locus-by-locus breakdown to trace the differing results to subtle differences in modeling parameters and methods, analytic thresholds, and mixture ratios, as well as TrueAllele's use of an ad hoc procedure for assigning LRs at some loci. These findings illustrate the extent to which PG analysis rests on a lattice of contestable assumptions, highlighting the importance of rigorous validation of PG programs using known-source test samples that closely replicate the characteristics of evidentiary samples. The article also points out misleading aspects of the way STRMix and TrueAllele results are routinely presented in reports and testimony and calls for clarification of forensic reporting standards to address those problems.
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Affiliation(s)
- William C Thompson
- Department of Criminology, Law & Society, University of California, Irvine, California, USA
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20
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Duijs FE, Meijers E, Kokshoorn B, Sijen T. Comparison of genotyping and weight of evidence results when applying different genotyping strategies on samples from a DNA transfer experiment. Int J Legal Med 2023; 137:47-56. [PMID: 36416964 DOI: 10.1007/s00414-022-02918-7] [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: 08/18/2022] [Accepted: 11/15/2022] [Indexed: 11/24/2022]
Abstract
In this study, we assessed to what extent data on the subject of TPPR (transfer, persistence, prevalence, recovery) that are obtained through an older STR typing kit can be used in an activity-level evaluation for a case profiled with a more modern STR kit. Newer kits generally hold more loci and may show higher sensitivity especially when reduced reaction volumes are used, and this could increase the evidential value at the source level. On the other hand, the increased genotyping information may invoke a higher number of contributors in the weight of evidence calculations, which could affect the evidential values as well. An activity scenario well explored in earlier studies [1,2] was redone using volunteers with known DNA profiles. DNA extracts were analyzed with three different approaches, namely using the optimal DNA input for (1) an older and (2) a newer STR typing system, and (3) using a standard, volume-based input combined with replicate PCR analysis with only the newer STR kit. The genotyping results were analyzed for various aspects such as percentage detected alleles and relative peak height contribution for background and the contributors known to be involved in the activity. Next, source-level LRs were calculated and the same trends were observed with regard to inclusionary and exclusionary LRs for persons who had or had not been in direct contact with the sampled areas. We subsequently assessed the impact on the outcome of the activity-level evaluation in an exemplary case by applying the assigned probabilities to a Bayesian network. We infer that data from different STR kits can be combined in the activity-level evaluations.
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Affiliation(s)
- Francisca E Duijs
- Division of Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands
| | - Erin Meijers
- Division of Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands
| | - Bas Kokshoorn
- Division of Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands.,Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands
| | - Titia Sijen
- Division of Biological Traces, Netherlands Forensic Institute, The Hague, The Netherlands. .,University of Amsterdam, Swammerdam Institute for Life Sciences, Amsterdam, The Netherlands.
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21
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Reither JB, van Oorschot RAH, Szkuta B. DNA transfer between worn clothing and flooring surfaces with known histories of use. Forensic Sci Int Genet 2022; 61:102765. [PMID: 36007265 DOI: 10.1016/j.fsigen.2022.102765] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 07/27/2022] [Accepted: 08/14/2022] [Indexed: 11/04/2022]
Abstract
DNA samples recovered from items of clothing are often attributed to the wearer and one or more individuals who may have contacted the item during an alleged criminal activity. Another scenario often proposed by defence counsel is that DNA was transferred from a previously contacted item/surface unrelated to the activity of interest onto the item of clothing. Under such scenarios, DNA may also be transferred from the clothing to the item/surface with which it comes into contact. One such surface is flooring, upon which clothing may be placed while not being worn or may be contacted during wearing, such as falling or being forced to the ground. This study investigates the transfer of DNA to and from clothing and flooring when different contacts are applied between the two surfaces in an environment representative of what investigators would encounter in routine casework, a residential environment. Participants were provided with two sets of new and unused upper and lower garments to wash then wear for ~8 h inside their own home before storing them in paper evidence bags. The two sets of clothing were taken to a home occupied by unrelated individuals, where one set was placed on the floor ('passive') by the researcher while the other was worn by the participant who laid with their back on the floor, rolled to one side and back, then stood up ('active'). Within the houses sampled, the main bedroom was targeted as flooring types and histories of use were more consistent across houses and less variation in DNA profile composition was previously observed for samples collected in the same room. Samples were collected from predetermined areas of the clothing and flooring where contact did and did not occur. Reference profiles were obtained from wearers and individuals they lived with, as well as occupants of the home. DNA transfer was observed from clothing to flooring and from flooring to clothing in both 'active' and 'passive' situations, though greater where a situation involved the application of pressure and friction ('active'), and only where contact between clothing and flooring occurred. Results from this study inform on the composition of DNA profiles one is likely to obtain from an item of clothing or a flooring surface following a similar contact event between the two substrates and will aid investigators when interpreting DNA evidence recovered in a domestic environment and the activities leading to its transfer and subsequent recovery.
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Affiliation(s)
- Jack B Reither
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia; Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC 3085, Australia.
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC 3085, Australia; School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC 3086, Australia
| | - Bianca Szkuta
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia
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22
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Johannessen H, Gill P, Shanthan G, Fonneløp AE. Transfer, persistence and recovery of DNA and mRNA vaginal mucosa markers after intimate and social contact with Bayesian network analysis for activity level reporting. Forensic Sci Int Genet 2022; 60:102750. [PMID: 35914368 DOI: 10.1016/j.fsigen.2022.102750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 01/25/2023]
Abstract
In sexual assault cases, it can be challenging to identify the type of body fluids/ cell types present in a crime scene sample, especially the origin of epithelial cells. Therefore, more labs are applying mRNA body fluid analysis for saliva, skin and vaginal mucosa markers. To address activity level propositions, it is necessary to assign probabilities of transfer, persistence, prevalence and recovery of DNA and mRNA markers. In this study we analysed 158 samples (fingernail swabs, penile swabs and boxershorts) from 12 couples collected at different time points post intimate contact and after non-intimate contact in order to detect DNA from the person of interest (POI) and mRNA vaginal mucosa markers. Samples were DNA and RNA co-extracted and analysed with PowerPlex®Fusion 6C System and 19-plex mRNA primer mix respectively, using Endpoint PCR and the CE platform. Vaginal mucosa was detected up to 36 h post intimate contact, but also detected in one non-intimate contact sample. In 94% of intimate contact and 50 % of non-intimate contact samples the DNA results support the proposition that POI is the donor (LR ≥ 10,000). There was a strong association between the detection of vaginal mucosa and the average RFU value of the POI. The data were used to instantiate a comprehensive Bayesian network to evaluate the evidence at activity level, given alternate propositions conditioned upon indirect or direct transfer events. It is shown that the value of the evidence is mainly affected by the high DNA quantity (measured as mean RFU) that is recovered from the POI. The detection of vaginal mucosa had low impact upon the resultant likelihood ratio.
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Affiliation(s)
| | - Peter Gill
- Department of Forensic Medicine, University of Oslo, Norway; Department of Forensic Sciences, Oslo University Hospital, Norway
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23
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Bini C, Giorgetti A, Giovannini E, Pelletti G, Fais P, Pelotti S. Technical note: Human DNA contamination of postmortem examination facilities: Impact of COVID-19 cleaning procedure. J Forensic Sci 2022; 67:1867-1875. [PMID: 35844155 PMCID: PMC9349986 DOI: 10.1111/1556-4029.15096] [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: 04/27/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022]
Abstract
The DNA contamination of evidentiary trace samples, included those collected in the autopsy room, has significant detrimental consequences for forensic genetics investigation. After the COVID‐19 pandemic, methods to prevent environmental contamination in the autopsy room have been developed and intensified. This study aimed to evaluate the level of human DNA contamination of a postmortem examination facility before and after the introduction of COVID‐19‐related disinfection and cleaning procedures. Ninety‐one swabs were collected from the surfaces and the dissecting instruments, analyzed by real‐time quantitative PCR (q‐PCR) and typed for 21 autosomal STRs. Sixty‐seven out of 91 samples resulted in quantifiable human DNA, ranging from 1 pg/μl to 12.4 ng/μl, including all the samples collected before the implementation of COVID‐19 cleaning procedures (n = 38) and 29 out of 53 (54.7%) samples taken afterward. All samples containing human DNA were amplified, resulting in mixed (83.6%), single (13.4%), and incomplete (3%) profiles. A statistically significant decrease in DNA contamination was found for dissecting instruments after treatment with chlorhexidine and autoclave (p < 0.05). Environmental decontamination strategies adopted during COVID‐19 pandemic only partially solved the long‐standing issue of DNA contamination of postmortem examination facilities. The pandemic represents an opportunity to further stress the need for standardized evidence‐based protocols targeted to overcome the problem of DNA contamination in the autopsy room.
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Affiliation(s)
- Carla Bini
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
| | - Arianna Giorgetti
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
| | - Elena Giovannini
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
| | - Guido Pelletti
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
| | - Paolo Fais
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
| | - Susi Pelotti
- Department of Medical and Surgical Sciences, Unit of Legal Medicine, University of Bologna, Bologna, Italy
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24
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Kelly H, Bright JA, Kruijver M, Taylor D, Buckleton J. The effect of a user selected number of contributors within the LR assignment. AUST J FORENSIC SCI 2022. [DOI: 10.1080/00450618.2020.1865456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Hannah Kelly
- Institute of Environmental Science and Research Limited, Auckland, New Zealand
| | - Jo-Anne Bright
- Institute of Environmental Science and Research Limited, Auckland, New Zealand
| | - Maarten Kruijver
- Institute of Environmental Science and Research Limited, Auckland, New Zealand
| | - Duncan Taylor
- School of Biological Sciences, Flinders University, Adelaide, Australia
- Forensic Science SA, Adelaide, Australia
| | - John Buckleton
- Institute of Environmental Science and Research Limited, Auckland, New Zealand
- Department of Statistics, University of Auckland, Auckland, New Zealand
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25
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Murphy C, Ryan J. Evaluative approach to semen transfer in a case of alleged sexual assault: A case study. Sci Justice 2022; 62:448-454. [DOI: 10.1016/j.scijus.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 03/29/2022] [Accepted: 05/31/2022] [Indexed: 10/17/2022]
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26
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Li Z, Li Y, Liu N, Yuan F, Liu F, Liu J, Yun K, Yan J, Zhang G. Typing of semen-containing mixtures using ARMS-based semen-specific CpG-InDel/STR markers. Int J Legal Med 2022; 136:1163-1176. [PMID: 35633397 DOI: 10.1007/s00414-022-02843-9] [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: 01/31/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
Abstract
Mixed traces are common biological materials found at crime scenes, and their identification remains a significant challenge in the field of forensic genetics. In recent years, DNA methylation has been considered as a promising approach for body fluid identification, and length polymorphic loci are still the preferred markers for personal identification. In this study, we used tissue-specific CpG sites with linked insertion or deletion (InDel) or short tandem repeat (STR) markers (CpG-InDel/STR) for both body fluid and individual identification. The tissue-specific CpG loci, which were all selected from the previous reports, were analyzed using a combination of bisulfite conversion and amplification refractory mutation system-multiprimer-PCR technology. InDels or STRs, which were selected within 400 bp upstream or downstream of the semen-specific CpG loci, were analyzed using a capillary electrophoresis platform. Eventually, we successfully constructed a panel containing 17 semen-specific CpG-InDel/STR compound markers compassing 21 InDels/STRs, 3 body-fluid positive controls (vaginal secretion-, saliva-, and blood-specific CpG), and 1 gender identification locus. Using this panel, full genotyping of individuals could be obtained successfully with 50 ng DNA input. Semen stains stored at room temperature for 7 months and degraded samples that were heat treated for up to 6 h were still identified efficiently. For semen containing mixed stains, it is also useful when the semen content is as low as 3.03%. Moreover, the cumulative discrimination power of this panel is 0.9999998. In conclusion, it is a robust panel enabling the validation of both the tissue source and individual identification of semen containing mixed stains and can be employed as an alternative solution for forensic case investigation.
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Affiliation(s)
- Zeqin Li
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Yidan Li
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Na Liu
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Fang Yuan
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Feng Liu
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Jinding Liu
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Keming Yun
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China
| | - Jiangwei Yan
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China.
| | - Gengqian Zhang
- School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi, 030619, People's Republic of China.
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Hicks T, Buckleton J, Castella V, Evett I, Jackson G. A Logical Framework for Forensic DNA Interpretation. Genes (Basel) 2022; 13:genes13060957. [PMID: 35741719 PMCID: PMC9223060 DOI: 10.3390/genes13060957] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 02/06/2023] Open
Abstract
The forensic community has devoted much effort over the last decades to the development of a logical framework for forensic interpretation, which is essential for the safe administration of justice. We review the research and guidelines that have been published and provide examples of how to implement them in casework. After a discussion on uncertainty in the criminal trial and the roles that the DNA scientist may take, we present the principles of interpretation for evaluative reporting. We show how their application helps to avoid a common fallacy and present strategies that DNA scientists can apply so that they do not transpose the conditional. We then discuss the hierarchy of propositions and explain why it is considered a fundamental concept for the evaluation of biological results and the differences between assessing results given propositions that are at the source level or the activity level. We show the importance of pre-assessment, especially when the questions relate to the alleged activities, and when transfer and persistence need to be considered by the scientists to guide the court. We conclude with a discussion on statement writing and testimony. This provides guidance on how DNA scientists can report in a balanced, transparent, and logical way.
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Affiliation(s)
- Tacha Hicks
- Forensic Genetics Unit, University Center of Legal Medicine, Lausanne—Geneva, Lausanne University Hospital and University of Lausanne, 1000 Lausanne 25, Switzerland;
- Fondation pour la Formation Continue Universitaire Lausannoise (UNIL-EPFL) & School of Criminal Justice, Batochime, 1015 Lausanne, Switzerland
- Correspondence:
| | - John Buckleton
- Department of Statistics, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
- Institute of Environmental Science and Research Limited, Private Bag 92021, Auckland 1142, New Zealand
| | - Vincent Castella
- Forensic Genetics Unit, University Center of Legal Medicine, Lausanne—Geneva, Lausanne University Hospital and University of Lausanne, 1000 Lausanne 25, Switzerland;
| | - Ian Evett
- Principal Forensic Services Ltd., Bromley BR1 2EB, UK;
| | - Graham Jackson
- Advance Forensic Science, St. Andrews KY16 0NA, UK;
- School of Applied Sciences, Division of Psychology and Forensic Science, Abertay University, Bell Street, Dundee DD1 1HG, UK
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28
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Yoon JY, Prinz M, McKiernan H, Oldoni F. American forensic DNA practitioners' opinion on activity level evaluative reporting. J Forensic Sci 2022; 67:1357-1369. [PMID: 35568965 DOI: 10.1111/1556-4029.15063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/28/2022] [Accepted: 05/05/2022] [Indexed: 11/28/2022]
Abstract
The technical advancements made in DNA profiling now allow for very low DNA amounts to be analyzed. Accordingly, the argument often made in criminal courts is not who the DNA belongs to but rather how it was deposited. Despite the complexity of the relevant DNA transfer, persistence, prevalence, and recovery issues, forensic laboratories in some European countries have used evaluative reports with activity level propositions, while this is not current practice in the United States. The purpose of this study was to gain an overview of the opinions about activity level reporting (ALR) held by forensic biologists in the United States. A seventeen-question survey was distributed to members of the American Society of Crime Laboratory Directors and U.S. members of the International Society for Forensic Genetics. The survey included multiple-choice and open-response questions and received 54 responses. The majority of responses expressed moderate support of ALR. Participants mentioned six major concerns to be addressed prior to implementing ALR in the United States: (1) effect of number of variables involved; (2) need of education for practitioners/legal system; (3) inadequate number of activity studies with realistic scenarios; (4) difficulty of achieving admissibility in court; (5) need for standardized approaches/guidelines; and (6) requisite shift in perspective as to the validity of ALR. Overall, this small segment of U.S. forensic DNA practitioners appear to be willing to implement ALR once these concerns are fully addressed and resolved. As a follow-up, it would be worthwhile exploring these and other questions with a larger group and also other disciplines.
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Affiliation(s)
- Jung Yang Yoon
- Department of Chemistry & Physics, Arcadia University, Glenside, Pennsylvania, USA
| | - Mechthild Prinz
- John Jay College of Criminal Justice, New York, New York, USA
| | - Heather McKiernan
- Center of Forensic Science and Research Education, Willow Grove, Pennsylvania, USA
| | - Fabio Oldoni
- Department of Chemistry & Physics, Arcadia University, Glenside, Pennsylvania, USA
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29
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Uitdehaag S, Donders T, Kuiper I, Wagner-Cremer F, Sjerps M. Use of Bayesian networks in forensic soil casework. Sci Justice 2022; 62:229-238. [DOI: 10.1016/j.scijus.2022.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 01/21/2022] [Accepted: 02/13/2022] [Indexed: 11/25/2022]
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30
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Use of Bayesian Networks for the investigation of the nature of biological material in casework. Forensic Sci Int 2022; 331:111174. [PMID: 34999364 DOI: 10.1016/j.forsciint.2022.111174] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/14/2021] [Accepted: 01/01/2022] [Indexed: 02/05/2023]
Abstract
Chemical and staining methods, immunochromatography, spectroscopy, RNA expression or methylation patterns, do not allow to determine the nature of the biological material with certainty. However, to our knowledge, there are few forensic scientists that assess the value of such test results using a probabilistic approach. This is surprising as it would allow account for false positives and false negatives and avoid misleading conclusions. In this paper, we developed three Bayesian Networks (BNs) to assess the presence of blood, saliva and sperm in the recovered material and combine potentially contradictory observations. The approach was successfully tested using 188 traces from proficiency tests. We have implemented an online user-friendly application (https://forensic-genetic.shinyapps.io/BodyFluidsApp/) that allows forensic scientists to assess the value of their results without having to build Bayesian Networks themselves. They can also input their own data, use the application to identify a potential lack of knowledge and report their conclusions regarding the presence of sperm, blood or/and saliva considering uncertainty.
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31
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Who Packed the Drugs? Application of Bayesian Networks to Address Questions of DNA Transfer, Persistence, and Recovery from Plastic Bags and Tape. Genes (Basel) 2021; 13:genes13010018. [PMID: 35052357 PMCID: PMC8774669 DOI: 10.3390/genes13010018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/23/2022] Open
Abstract
When DNA from a suspect is detected in a sample collected at a crime scene, there can be alternative explanations about the activity that may have led to the transfer, persistence and recovery of his/her DNA. Previous studies have shown that DNA can be indirectly transferred via intermediate surfaces and that DNA on a previously used object can persist after subsequent use of another individual. In addition, it has been shown that a person’s shedder status may influence transfer, persistence, prevalence, and recovery of DNA. In this study we have investigated transfer persistence and recovery on zip-lock bags and tape, which are commonly encountered in drug cases and how the shedder status of the participants influenced the results. A probabilistic framework was developed which was based on a previously described Bayesian network with case-specific modifications. Continuous modelling of data was used to inform the Bayesian networks and two case scenarios were investigated. In the specific scenarios only moderate to low support for Hp was obtained. Applying a continuous model based on the profile quality can change the LRs.
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32
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Wienroth M, Granja R, Lipphardt V, Nsiah Amoako E, McCartney C. Ethics as Lived Practice. Anticipatory Capacity and Ethical Decision-Making in Forensic Genetics. Genes (Basel) 2021; 12:1868. [PMID: 34946816 PMCID: PMC8701090 DOI: 10.3390/genes12121868] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 01/12/2023] Open
Abstract
Greater scrutiny and demands for innovation and increased productivity place pressures on scientists. Forensic genetics is advancing at a rapid pace but can only do so responsibly, usefully, and acceptably within ethical and legal boundaries. We argue that such boundaries require that forensic scientists embrace 'ethics as lived practice'. As a starting point, we critically discuss 'thin' ethics in forensic genetics, which lead to a myopic focus on procedures, and to seeing 'privacy' as the sole ethical concern and technology as a mere tool. To overcome 'thin' ethics in forensic genetics, we instead propose understanding ethics as an intrinsic part of the lived practice of a scientist. Therefore, we explore, within the context of three case studies of emerging forensic genetics technologies, ethical aspects of decision-making in forensic genetics research and in technology use. We discuss the creation, curation, and use of databases, and the need to engage with societal and policing contexts of forensic practice. We argue that open communication is a vital ethical aspect. Adoption of 'ethics as lived practice' supports the development of anticipatory capacity-empowering scientists to understand, and act within ethical and legal boundaries, incorporating the operational and societal impacts of their daily decisions, and making visible ethical decision making in scientific practice.
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Affiliation(s)
- Matthias Wienroth
- Centre for Crime and Policing, Department of Social Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK
| | - Rafaela Granja
- Communication and Society Research Centre, University of Minho, 4710-057 Braga, Portugal
| | - Veronika Lipphardt
- University College Freiburg, Albert-Ludwigs-Universität, 79098 Freiburg, Germany
| | - Emmanuel Nsiah Amoako
- Department of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Carole McCartney
- Science & Justice Research Interest Group, Law School, Northumbria University, Newcastle upon Tyne NE1 8ST, UK
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33
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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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34
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Attinger D, De Brabanter K, Champod C. Using the likelihood ratio in bloodstain pattern analysis. J Forensic Sci 2021; 67:33-43. [PMID: 34713435 DOI: 10.1111/1556-4029.14899] [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: 01/17/2021] [Revised: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 11/27/2022]
Abstract
There is an apparent paradox that the likelihood ratio (LR) approach is an appropriate measure of the weight of evidence when forensic findings have to be evaluated in court, while it is typically not used by bloodstain pattern analysis (BPA) experts. This commentary evaluates how the scope and methods of BPA relate to several types of evaluative propositions and methods to which LRs are applicable. As a result of this evaluation, we show how specificities in scope (BPA being about activities rather than source identification), gaps in the underlying science base, and the reliance on a wide range of methods render the use of LRs in BPA more complex than in some other forensic disciplines. Three directions are identified for BPA research and training, which would facilitate and widen the use of LRs: research in the underlying physics; the development of a culture of data sharing; and the development of training material on the required statistical background. An example of how recent fluid dynamics research in BPA can lead to the use of LR is provided. We conclude that an LR framework is fully applicable to BPA, provided methodic efforts and significant developments occur along the three outlined directions.
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Affiliation(s)
| | - Kris De Brabanter
- Department of Statistics, Iowa State University, Ames, Iowa, USA.,Department of Industrial Manufacturing & Systems Engineering, Iowa State University, Ames, Iowa, USA
| | - Christophe Champod
- Ecole des Sciences Criminelles, Faculty of Law, Criminal Justice and Public Administration, Université de Lausanne, Lausanne, Switzerland
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35
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Sijen T, Harbison S. On the Identification of Body Fluids and Tissues: A Crucial Link in the Investigation and Solution of Crime. Genes (Basel) 2021; 12:1728. [PMID: 34828334 PMCID: PMC8617621 DOI: 10.3390/genes12111728] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 12/13/2022] Open
Abstract
Body fluid and body tissue identification are important in forensic science as they can provide key evidence in a criminal investigation and may assist the court in reaching conclusions. Establishing a link between identifying the fluid or tissue and the DNA profile adds further weight to this evidence. Many forensic laboratories retain techniques for the identification of biological fluids that have been widely used for some time. More recently, many different biomarkers and technologies have been proposed for identification of body fluids and tissues of forensic relevance some of which are now used in forensic casework. Here, we summarize the role of body fluid/ tissue identification in the evaluation of forensic evidence, describe how such evidence is detected at the crime scene and in the laboratory, elaborate different technologies available to do this, and reflect real life experiences. We explain how, by including this information, crucial links can be made to aid in the investigation and solution of crime.
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Affiliation(s)
- Titia Sijen
- Division Human Biological Traces, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497 GB The Hague, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - SallyAnn Harbison
- Institute of Environmental Science and Research Limited, Private Bag 92021, Auckland 1142, New Zealand;
- Department of Statistics, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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36
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Interpretation of DNA data within the context of UK forensic science - evaluation. Emerg Top Life Sci 2021; 5:405-413. [PMID: 34027985 PMCID: PMC8760892 DOI: 10.1042/etls20200340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/24/2021] [Accepted: 05/04/2021] [Indexed: 12/30/2022]
Abstract
Forensic DNA provides a striking contribution to the provision of justice worldwide. It has proven to be crucial in the investigative phase of an unsolved crime where a suspect needs to be identified, e.g. from a DNA database search both nationally and internationally. It is also a powerful tool in the assignment of evidential weight to the comparison of a profile of a person of interest and a crime scene profile. The focus of this document is the evaluation of autosomal profiles for criminal trials in the UK. A separate review covers investigation and evaluation of Y-STR profiles, investigation using autosomal profiles, kinship analysis, body identification and Forensic Genetic Genealogy investigations. In less than 40 years, forensic DNA profiling has developed from a specialist technique to everyday use. Borrowing on advances in genome typing technology, forensic DNA profiling has experienced a substantial increase in its sensitivity and informativeness. Alongside this development, novel interpretation methodologies have also been introduced. This document describes the state of the art and future advances in the interpretation of forensic DNA data.
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37
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Riman S, Iyer H, Vallone PM. Examining performance and likelihood ratios for two likelihood ratio systems using the PROVEDIt dataset. PLoS One 2021; 16:e0256714. [PMID: 34534241 PMCID: PMC8448353 DOI: 10.1371/journal.pone.0256714] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/07/2021] [Indexed: 11/30/2022] Open
Abstract
A likelihood ratio (LR) system is defined as the entire pipeline of the measurement and interpretation processes where probabilistic genotyping software (PGS) is a piece of the whole LR system. To gain understanding on how two LR systems perform, a total of 154 two-person, 147 three-person, and 127 four-person mixture profiles of varying DNA quality, DNA quantity, and mixture ratios were obtained from the filtered (.CSV) files of the GlobalFiler 29 cycles 15s PROVEDIt dataset and deconvolved in two independently developed fully continuous programs, STRmix v2.6 and EuroForMix v2.1.0. Various parameters were set in each software and LR computations obtained from the two software were based on same/fixed EPG features, same pair of propositions, number of contributors, theta, and population allele frequencies. The ability of each LR system to discriminate between contributor (H1-true) and non-contributor (H2-true) scenarios was evaluated qualitatively and quantitatively. Differences in the numeric LR values and their corresponding verbal classifications between the two LR systems were compared. The magnitude of the differences in the assigned LRs and the potential explanations for the observed differences greater than or equal to 3 on the log10 scale were described. Cases of LR < 1 for H1-true tests and LR > 1 for H2-true tests were also discussed. Our intent is to demonstrate the value of using a publicly available ground truth known mixture dataset to assess discrimination performance of any LR system and show the steps used to understand similarities and differences between different LR systems. We share our observations with the forensic community and describe how examining more than one PGS with similar discrimination power can be beneficial, help analysts compare interpretation especially with low-template profiles or minor contributor cases, and be a potential additional diagnostic check even if software in use does contain certain diagnostic statistics as part of the output.
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Affiliation(s)
- Sarah Riman
- Applied Genetics Group, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Hari Iyer
- Statistical Design, Analysis, Modeling Group, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Peter M. Vallone
- Applied Genetics Group, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
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38
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Vennemann M, Oppelt C, Grethe S, Anslinger K, Fimmers R, Schneider H, Hohoff C, Eckert M, Rothämel T, Schneider PM. Möglichkeiten und Grenzen der forensischen DNA-Analyse unter dem Gesichtspunkt verschiedener Szenarien zur Spurenentstehung. Rechtsmedizin (Berl) 2021. [DOI: 10.1007/s00194-021-00508-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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39
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Thornbury D, Goray M, van Oorschot RAH. Drying properties and DNA content of saliva samples taken before, during and after chewing gum. AUST J FORENSIC SCI 2021. [DOI: 10.1080/00450618.2021.1931444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Devon Thornbury
- School of Life Sciences, La Trobe University, Bundoora, Australia
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Australia
| | - Mariya Goray
- Biometrics Division, Victoria Police Forensic Services Department, Macleod, Australia
| | - Roland A. H. van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Australia
- School of Molecular Sciences, La Trobe University, Bundoora, Australia
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40
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Johannessen H, Gill P, Roseth A, Fonneløp AE. Determination of shedder status: A comparison of two methods involving cell counting in fingerprints and the DNA analysis of handheld tubes. Forensic Sci Int Genet 2021; 53:102541. [PMID: 34090062 DOI: 10.1016/j.fsigen.2021.102541] [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: 04/07/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 01/13/2023]
Abstract
The shedder status of an individual may be important to consider in the context of DNA transfer, persistence and recovery and in Bayesian networks where a person's shedder status may have an impact on the outcome. In this study we compared two methods to determine shedder status: the handheld tube (HH) method and a fluorescent cell count (CC) method. A poor association was observed between the numbers of detected cells in a fingerprint using the CC method and the strength of the DNA result with the HH method. The 20 participants were classified into low (25%), medium (50%) and high (25%) shedders based on the HH method. While the low and high shedders showed a good consistency between the replicates, the medium shedders varied more and have to be considered more carefully as they may act as either a high or a low shedder in an event of DNA transfer.
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Affiliation(s)
- Helen Johannessen
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Norway.
| | - Peter Gill
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Norway; Department of Forensic Sciences, Oslo University Hospital, Norway
| | - Arne Roseth
- Department of Forensic Sciences, Oslo University Hospital, Norway
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41
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The prevalence and persistence of saliva in vehicles. Forensic Sci Int Genet 2021; 53:102530. [PMID: 34058533 DOI: 10.1016/j.fsigen.2021.102530] [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: 09/30/2020] [Revised: 04/25/2021] [Accepted: 05/07/2021] [Indexed: 11/23/2022]
Abstract
In forensic investigations involving stolen and crashed vehicles, examining airbags for the presence of saliva is useful strategy in order to try and establish who the driver of the vehicle may have been. The use of an evaluative approach in these types of investigations allows the forensic scientist to evaluate the significance of the evidence with regard to two alternative hypothesis. The presence of saliva on an airbag may be the result of the driver coming into contact with it during an impact. Alternatively, the saliva may have transferred to the airbag from another area in the vehicle following its deployment. To address this question and attach significance to this finding, a dataset on the prevalence and persistence of saliva is required, alongside relevant background information on the case. The purpose of this study was to determine if saliva matching the main driver of a vehicle is present in the areas immediately surrounding the driver's section, and also to determine the persistence of saliva in vehicles. Salivary-α-amylase was detected in 53% of all samples collected from vehicles. Saliva positive samples yielded statistically significantly (p<0.05) more DNA than saliva negative samples. There was no statistical difference in DNA yields from the different areas sampled in the vehicles. The steering wheel was observed to have the greatest number of saliva positive samples (80%). The driver's DNA profile was detected in 72% of the total samples taken. We demonstrated that saliva can persist for at least ten days in vehicles in daily use. This study has produced a useful dataset that can be utilised under certain conditions by forensic investigators when taking an evaluative approach to these particular types of forensic investigations.
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Systematic STR analysis of old post-vasectomy seminal fluid stains to examine evidence stored for 16 years. Sci Rep 2021; 11:8918. [PMID: 33903633 PMCID: PMC8076208 DOI: 10.1038/s41598-021-87937-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/05/2021] [Indexed: 12/02/2022] Open
Abstract
To understand stored evidence and the insertion in genetic databases is important in forensic investigations. Blood, pre- and post-vasectomy semen from 90 fertile male individuals, aged 24 to 45, were donated for research after informed consent. The semen samples were stored in the form of 30 µL stains on cotton fabric, for 16 years at room temperature in the laboratory. As well as the seminal fluid post vasectomy stains, which were performed after microscopy analyzes and certainty of the absence of spermatozoon. The pre vasectomy stains contained mainly haploid spermatozoon and the post vasectomy stains diploid epithelial cells and leukocytes. DNA extraction was performed with magnetic resin, followed by quantification and analysis of degradation of DNA. In this study we analyze these genetic profiles of DNA from stains on cotton fabric, using two Short Tandem Repeat multiplex systems, the PowerPlex Fusion 6C and Y23. Electrophoresis was performed on a 3500xL and analyzed using the Gene Mapper ID-X software. The genetic profiles of the 90 individuals were fully amplified in pre-vasectomy and partially in post-vasectomy stain samples, using the both multiplex systems. The results provide information about 0.25 cm2 semen stains on cotton fabric from 90 individuals, correlating concentration, degradation, and allele analysis. It also provides an understanding of the cells present in semen stains and the implications of individual factors. In the stains of post-vasectomy samples the small quantity of DNA was one of the limiting factors, in addition to degradation. Considering that all evaluations were carried out in a laboratory that has a quality control certificate and audited for being part of the national genetic profile database, the results were very consistent. Many aspects of the semen samples stored in the form of stains on cotton fabric have been clarified. The performance and sensitivity of the amplification systems used in the genotyping of azoospermic individuals were assessed. Conclusions: Genetic profiles were satisfactorily amplified in pre-vasectomy stain samples, and partially amplified in post-vasectomy stain samples, stored for almost two decades at room temperature in a tropical country. The small amount of DNA was one of the limitations in post-vasectomy stain samples, in addition to degradation and fragmentation. There are no publications in the literature on PowerPlex Fusion 6C and Y23 analyses using blood, sperm, and seminal fluids of the same individual, much less in the form of stains. This study can serve as a benchmark for the tracking analyses of stored samples. In addition, it anticipates a few social issues related to the analysis of post-vasectomy samples in forensic cases, most notably sex crimes.
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Taylor D, Volgin L, Kokshoorn B, Champod C. The importance of considering common sources of unknown DNA when evaluating findings given activity level propositions. Forensic Sci Int Genet 2021; 53:102518. [PMID: 33865097 DOI: 10.1016/j.fsigen.2021.102518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/03/2021] [Accepted: 03/30/2021] [Indexed: 01/27/2023]
Abstract
Evaluating forensic biological evidence considering activity level propositions is becoming more prominent around the world. In such evaluations it is common to combine results from multiple items associated with the alleged activities. The results from these items may not be conditionally independent, depending on the mechanism of cell/DNA transfer being considered and it is important that the evaluation takes these dependencies into account. Part of this consideration is to incorporate our understanding of prevalent DNA and of background DNA on objects and people, and how activities can lead to common sources of unknown DNA being deposited on items. We demonstrate a framework for evaluation of DNA evidence in such a scenario using Object-Oriented Bayesian Networks and apply it to a motivating case from South Australia.
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Affiliation(s)
- Duncan Taylor
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia; Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia.
| | - Luke Volgin
- Forensic Science SA, GPO Box 2790, Adelaide, South Australia 5001, Australia
| | - Bas Kokshoorn
- Netherlands Forensic Institute, P.O. Box 24044, NL-2490AA The Hague, the Netherlands
| | - Christophe Champod
- Faculty of Law, Criminal Justice and Public Administration, School of Criminal Justice, University of Lausanne, CH-1015 Lausanne-Dorigny, Switzerland
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A generalised Bayes' factor formula for evidence evaluation under activity level propositions: Variations around a fibres scenario. Forensic Sci Int 2021; 322:110750. [PMID: 33784544 DOI: 10.1016/j.forsciint.2021.110750] [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: 10/04/2020] [Revised: 02/07/2021] [Accepted: 03/08/2021] [Indexed: 11/24/2022]
Abstract
Generalised Bayes' factors and associated Bayesian networks are developed for the transfer of extrinsic evidence at the activity level, developments that extend previous work on activity level evaluation. A strategy for the assessment of extrinsic evidence is developed in stages with progressive increases in complexity. The final development is illustrated with an example involving fibres from clothing. This provides a list of factors involved in the consideration of a transfer case with activity level propositions and their roles in the determination of evidential value.
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Airlie M, Robertson J, Krosch MN, Brooks E. Contemporary issues in forensic science-Worldwide survey results. Forensic Sci Int 2021; 320:110704. [PMID: 33581657 DOI: 10.1016/j.forsciint.2021.110704] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/23/2020] [Accepted: 01/19/2021] [Indexed: 01/28/2023]
Abstract
Forensic science continues to be openly challenged and criticized. The aim of this study was to gain an understanding of forensic workplaces and the perceived current and potential future issues from forensic scientists via a detailed survey. An online survey was designed and disseminated to forensic practitioners and researchers worldwide. 544 participants from more than 20 countries took part in the survey. Participants personally rated ten forensic disciplines with subjective methodologies, responded on a five-point Likert scale to 22 statements that addressed subjectivity and objectivity, validation and proficiency testing and error and bias and answered demographic questions relating to their workplace type, level of experience and qualifications. Participants also commented freely on forensic issues specifically important to them. The purpose of this paper is to provide the survey results and consensuses captured on several key issues. Overall participants believed forensic science must be valid and reliable and supported development of objective methodologies, validation and further investigation into the application statistics, use of error rates and implications of cognitive bias. Participants raised consensus concerns with the provision of expert evidence and other broader issues. This information and understanding from the forensic front line are essential for forensic science moving forward to best address current challenges and criticisms not only of forensic evidence for the court but for applications of forensic science beyond the courtroom.
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Affiliation(s)
- Melissa Airlie
- University of Canberra, National Centre for Forensic Studies, Faculty of Science and Technology, 11 Kirinari Street, Bruce, ACT, 2617, Australia; Forensic Services Group, Queensland Police Service, Level 4, 200 Roma Street, Brisbane, Queensland, 4000, Australia.
| | - James Robertson
- University of Canberra, National Centre for Forensic Studies, Faculty of Science and Technology, 11 Kirinari Street, Bruce, ACT, 2617, Australia
| | - Matt N Krosch
- Forensic Services Group, Queensland Police Service, Level 4, 200 Roma Street, Brisbane, Queensland, 4000, Australia
| | - Elizabeth Brooks
- University of Canberra, National Centre for Forensic Studies, Faculty of Science and Technology, 11 Kirinari Street, Bruce, ACT, 2617, Australia
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Thornbury D, Goray M, van Oorschot RAH. Indirect DNA transfer without contact from dried biological materials on various surfaces. Forensic Sci Int Genet 2020; 51:102457. [PMID: 33465559 DOI: 10.1016/j.fsigen.2020.102457] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 11/16/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022]
Abstract
DNA transfer is a well-recognised phenomenon impacting the probability of detecting the presence of a particular source of DNA and thus the likelihood of the evidence given considered events within forensic investigations. Comprehensive study is lacking on variables associated with indirect DNA transfer without physical contact. Additionally, the drying properties of forensically relevant biological materials are under researched despite the recognised potential for these properties to affect DNA transfer. This study investigated the drying properties and indirect DNA transfer of dried blood, saliva, semen, vaginal fluid and touch DNA without contact deposited on two different non-porous hard substrates (melamine and glass) and two different porous soft substrates (polyester and cotton) by tapping (all substrates) and stretching (only fabric substrates) agitations. Different apparent drying trends were observed between the volumes, substrates and biological materials tested with substrate type generally having a greater influence than biological material. The rate and percentage of indirect transfer appeared to be dependent on agitation, substrate type, biological material and its drying properties. The outcomes of this study may assist those evaluating the likelihood of the evidence given proposed events during activity level assessments.
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Affiliation(s)
- Devon Thornbury
- School of Life Sciences, La Trobe University, Bundoora, Australia; Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Australia.
| | - Mariya Goray
- Biometrics Division, Victoria Police Forensic Services Department, Macleod, Australia
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Australia; School of Molecular Sciences, La Trobe University, Bundoora, Australia
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Meakin GE, Kokshoorn B, Oorschot RAH, Szkuta B. Evaluating forensic
DNA
evidence: Connecting the dots. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/wfs2.1404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Georgina E. Meakin
- Centre for Forensic Science University of Technology Sydney Ultimo NSW Australia
- Centre for the Forensic Sciences, Department of Security and Crime Science University College London London UK
| | - Bas Kokshoorn
- Netherlands Forensic Institute The Hague The Netherlands
| | - Roland A. H. Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department Macleod Australia
- School of Molecular Sciences La Trobe University Bundoora Australia
| | - Bianca Szkuta
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department Macleod Australia
- School of Life and Environmental Sciences Deakin University Geelong Australia
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Biedermann A, Kotsoglou KN. Digital evidence exceptionalism? A review and discussion of conceptual hurdles in digital evidence transformation. Forensic Sci Int Synerg 2020; 2:262-274. [PMID: 32944711 PMCID: PMC7481130 DOI: 10.1016/j.fsisyn.2020.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 01/27/2023]
Abstract
Forensic science is currently undergoing a transformation and expansion to include modern types of evidence, such as evidence generated by digital investigations. This development is said to raise a series of challenges, both in operational and conceptual dimensions. This paper reviews and discusses a series of convoluted conceptual hurdles that are encountered in connection with the use of digital evidence as part of evidence and proof processes at trial, in contradistinction to investigative uses of such types of evidence. As a recent example raising such hurdles, we analyse and discuss assertions and proposals made in the article "Digital Evidence Certainty Descriptors (DECDs)" by Graeme Horsman (32 Forensic Science International: Digital Investigation (2020) 200896).
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Affiliation(s)
- Alex Biedermann
- University of Lausanne, School of Criminal Justice, 1015, Lausanne, Dorigny, Switzerland
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Pope S, Biedermann A. Editorial: The Dialogue Between Forensic Scientists, Statisticians and Lawyers About Complex Scientific Issues for Court. Front Genet 2020; 11:704. [PMID: 32849771 PMCID: PMC7427488 DOI: 10.3389/fgene.2020.00704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/10/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sue Pope
- Principal Forensic Services, Bromley, Kent, United Kingdom
| | - Alex Biedermann
- Faculty of Law, Criminal Justice and Public Administration, University of Lausanne, Lausanne, Switzerland
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A distant relationship?-investigation of correlations between DNA isolated from backspatter traces recovered from firearms, wound profile characteristics, and shooting distance. Int J Legal Med 2020; 134:1619-1628. [PMID: 32691136 PMCID: PMC8211572 DOI: 10.1007/s00414-020-02374-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/08/2020] [Indexed: 02/04/2023]
Abstract
In molecular ballistics, where traces originating from the use of firearms against biological targets are investigated, "backspatter" traces are of particular importance. This biological material comprising blood and tissue from the victim is propelled back from the bullet entry site towards the direction of the shooter and can consolidate and persist on the inner and outer surfaces of the firearm, from where it can be collected and analyzed. Thus, a connection between the weapon and the victim can be established solely by molecular biological trace analysis. For the criminalistic investigation of gun-related crimes, the determination of the distance between the weapon and the victim can be of critical importance in reconstructing the circumstances of a crime. In this study, we investigated possible correlations between the shooting distance and the amount of backspatter in/on the used firearm. To this purpose, we employed a previously established skull model and performed shootings in triplicates from various distances up to 50 cm with two types of handguns (pistol and revolver). Backspatter was collected from various sampling locations, and DNA contents were quantified. A post-shooting wound channel evaluation was conducted by optical and radiological evaluation. The obtained DNA yields varied considerably between replicates from the same and from different distances. In contrast, apart from contact shots, no meaningful differences were observable in wound channel evaluations. In summary, no meaningful correlation between backspatter distribution and DNA yields, the shooting distance and the condition of the wound channel could be established.
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