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Gegar MS, Cisneros GA, Cox J, Richard M, Currie KA. Saliva-derived secondary DNA transfer on fabric: The impact of varying conditions. Forensic Sci Int Genet 2024; 72:103092. [PMID: 38971087 DOI: 10.1016/j.fsigen.2024.103092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 06/02/2024] [Accepted: 06/27/2024] [Indexed: 07/08/2024]
Abstract
This study explored secondary DNA transfer involving saliva, a body fluid often encountered in forensic investigations. Various factors were examined to investigate their potential impact on the transfer of DNA from saliva stains deposited onto common types of fabric (cotton, nylon, and towel). We examined varying types of saliva moisture (wet, dry, and rehydrated) and different types of contact (controlled pressure and active/friction pressure) to quantitatively evaluate how such variables could impact transfer and possible conclusions surrounding saliva-derived DNA deposits. The transfer of DNA was generally least pronounced with more absorbent primary fabrics (cotton and towel materials) while a less absorbent primary fabric (nylon) exhibited a greater propensity for DNA transfer. There were significantly higher amounts of transferred DNA (p < 0.05) observed in wet saliva samples compared to dry and rehydrated saliva samples. Further, the use of active pressure (friction) appeared to result in more DNA transfer overall as compared to controlled pressure contact. Experiments conducted with wet saliva and active pressure (friction) demonstrated the highest likelihood of transfer, with the primary nylon and secondary towel fabric combination demonstrating the greatest average transfer percentage of 94.74 %. The variables explored in this study presented multiple combinations wherein a sufficient amount of DNA (≥ 240 pg total) was transferred to the secondary fabric, making it potentially suitable for STR-PCR amplification in our laboratory. The findings from this study indicate that the type of primary fabric receiving the saliva deposit, the type of saliva moisture, the type of secondary fabric and its moisture type, and the type of contact all have the potential to affect the quantity of DNA transferred and recovered. This study provides empirical data on the ease, and to what extent, DNA from saliva transfers between fabrics and aids DNA activity level evaluations. The significance of this research lies in its contribution to expanding our current understanding of DNA transfer involving saliva within forensic science and criminal investigations.
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Affiliation(s)
- Melanie S Gegar
- School of Natural Sciences, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada.
| | - German A Cisneros
- School of Natural Sciences, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada.
| | - Joanne Cox
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada.
| | - Melanie Richard
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada.
| | - Krista A Currie
- School of Natural Sciences, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada.
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2
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Cahill A, Volgin L, van Oorschot RAH, Taylor D, Goray M. Where did it go? A study of DNA transfer in a social setting. Forensic Sci Int Genet 2024; 73:103101. [PMID: 39096604 DOI: 10.1016/j.fsigen.2024.103101] [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: 03/20/2024] [Revised: 07/24/2024] [Accepted: 07/25/2024] [Indexed: 08/05/2024]
Abstract
The sensitivity of DNA analysis has progressed to the point that trace levels of DNA, originating from only a few cells, can generate informative profiles. This means that virtually any item or surface can be sampled with a reasonable chance of obtaining a DNA profile. As the presence of DNA does not suggest how it was deposited, questions are often raised as to how the DNA came to be at a particular location and the activity that led to its deposition. Therefore, understanding different modes of DNA deposition, reflective of realistic forensic casework situations, is critical for proper evaluation of DNA results in court. This study aimed to follow the movements of DNA to and from individuals and common household surfaces in a residential premises, while socially interacting. This took place over an hour and involved four participants, with known shedder status, designated as visitors (a male and a female) and hosts (a male and a female), who engaged in the activity of playing a board game while being served food. During the study, the participants were instructed to use the toilet on a single occasion to assess the transfer of DNA to new and unused underwear that was provided. All contacts made by the participants in the dining room and kitchen were video recorded to follow the movements of DNA. Samples were collected based on the history of contact, which included hands, fingernails and penile swabs. Direct contacts resulted in detectable transfer (LR > 1) in 87 % (87/100) of the non-intimate samples and clothing. For surfaces touched by multiple participants, DNA from the person who made the last contact was not always detectable. The duration and number of contacts did not significantly affect the detection of the person contacting the item. On the other hand, presence of background DNA and participant's shedder status appear to play an important role. Further, unknown contributors were detected in the majority of samples. Finally, indirect transfer was observed on a number of occasions including co-habiting partners of guests who were not present at the study location. The results of this study may assist with decision making for exhibit selection or targeting areas for sampling within the home environment. Our findings can also be used in conjunction with previous literature to develop activity-level evaluations in such situations where the source of the DNA is conceded, but the mode of deposition is disputed.
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Affiliation(s)
- Amy Cahill
- College of Science and Engineering, Flinders University, Bedford Park, South Australia, Australia
| | - Luke Volgin
- Forensic Science SA, GPO Box 2790, Adelaide 5001, Australia
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Victoria, Australia; School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia
| | - Duncan Taylor
- Forensic Science SA, GPO Box 2790, Adelaide 5001, Australia
| | - Mariya Goray
- College of Science and Engineering, Flinders University, Bedford Park, South Australia, Australia.
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3
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Roersma R, Storm J, Joling J, Kokshoorn B. Prevalence of male DNA on female worn undergarments. How small datasets may support robust opinions in activity level evaluative reporting. Forensic Sci Int 2024; 361:112097. [PMID: 38909409 DOI: 10.1016/j.forsciint.2024.112097] [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: 12/28/2023] [Revised: 05/23/2024] [Accepted: 06/06/2024] [Indexed: 06/25/2024]
Abstract
In cases of sexual assault, the interpretation of biological traces on clothing, and particularly undergarments, may be complex. This is especially so when the complainant and defendant interact socially, for instance as (ex-)partners or by co-habitation. Here we present the results from a study where latent male DNA on female worn undergarments is recovered in four groups with different levels of male-female social interaction. The results conform to prior expectation, in that less interaction tend to result in less male DNA on undergarments. We explore the use of these experimental data for evaluative reporting given activity level propositions in a mock case scenario. We show how the selection of different populations to represent the social interaction between complainant and defendant may affect the strength of the evidence. We further show how datasets of limited size can be used for robust activity level evaluative reporting.
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Affiliation(s)
- R Roersma
- Forensic Trace Dynamics, Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam (AUAS), the Netherlands; Netherlands Forensic Institute, The Hague, The Netherlands
| | - J Storm
- Forensic Trace Dynamics, Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam (AUAS), the Netherlands
| | - J Joling
- Forensic Trace Dynamics, Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam (AUAS), the Netherlands
| | - B Kokshoorn
- Forensic Trace Dynamics, Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam (AUAS), the Netherlands; Netherlands Forensic Institute, The Hague, The Netherlands.
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4
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Beveridge T, Szkuta B, van Oorschot RAH, Durdle A. The detection of blood, semen and saliva through fabrics: A pilot study. Forensic Sci Int 2024; 361:112153. [PMID: 39029141 DOI: 10.1016/j.forsciint.2024.112153] [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: 02/29/2024] [Revised: 07/09/2024] [Accepted: 07/16/2024] [Indexed: 07/21/2024]
Abstract
This study aimed to identify if biological material could be detected on the opposite side to deposition on fabric by commonly used presumptive and/or secondary tests. Additionally, this study aimed to ascertain if there is a difference in the DNA quantity and quality from samples obtained from both sides of the same substrate: cotton, polyester, denim, or combined viscose and polyester swatches. Blood, semen, or saliva (25 μL) was deposited on one side of 5 replicates of each fabric type and left for 24 h. Blood swatches were tested using Hemastix® and the ABACard® HemaTrace® immunoassay, semen swatches were tested using acid phosphatase (AP) reagent, the ABACard® p30® immunoassay and hematoxylin and eosin staining, and saliva swatches were tested using Phadebas® paper and the RSID-Saliva™ immunoassay. Both sides of each swatch were separately wet/dry swabbed and subjected to DNA analysis. Blood was able to be detected on the underside of all fabrics using both tests. Semen was able to be detected on the underside of swatches using the presumptive AP test but not p30®, and sperm was rarely observed. Saliva was able to be detected by RSID-Saliva™ but not Phadebas® paper when the underside of swatches were tested. Across all biological materials, DNA was able to be recovered from the top side of all 60 swatches. For the underside, DNA was able to be recovered from 54 swatches. Of the 6 swatches that DNA was unable to be recovered from, one sample was from semen and the rest were from saliva. This study has demonstrated that DNA and components of interest in forensically relevant biological material can be recovered from the opposite side to where it was originally deposited, and that observing biological material and/or DNA on one side of fabric does not definitively indicate direct deposition on that side.
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Affiliation(s)
- Tia Beveridge
- 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
| | - 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
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Kim BM, Park SU, Schmelzer L, Yang SB, Lee SD, Kim MY, Naue J, Lee HY. DNA methylation-based organ tissue identification: Marker identification, SNaPshot multiplex assay development, and interlaboratory comparison. Forensic Sci Int Genet 2024; 71:103052. [PMID: 38678764 DOI: 10.1016/j.fsigen.2024.103052] [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: 01/17/2024] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 05/01/2024]
Abstract
Identifying body fluids and organ tissues is highly significant as they can offer crucial evidence in criminal investigations and aid the court in making informed decisions, primarily through evaluating the biological source and possibly at the activity level up to death or fatal damage. In this study, organ tissue-specific CpG markers were identified from Illumina's methylation EPIC array data of nine organ tissues, including epidermis, dermis, heart, skeletal muscle, blood, kidney, brain, lung, and liver, from autopsies of 10 Koreans. Through the validation test using 43 samples, 18 hypomethylation markers, with two markers for each organ tissue type, were selected to construct a SNaPshot assay. Two multiplex assays involving forward and reverse SBE primers were designed to help investigators accurately determine the organ origin of the analyzed tissue samples through repeated analysis of the same PCR products for markers. The developed multiplex demonstrated high accuracy, achieving 100.0 % correct detection of the presence of nine organ tissue types in 88 samples from autopsies of 10 Asians. However, two lung samples showed additional positive indications of the presence of blood. An interlaboratory comparison using 80 autopsy samples (heart, skeletal muscle, blood, kidney cortex, kidney medulla, brain, lung, and liver) from 10 individuals in Germany revealed overall comparable results with correct detection of the presence of eight organ tissue types in 92.5 % samples (74 of 80 samples). In the case of six samples, it was impossible to determine the correct tissue successfully due to drop-outs of unmethylation signals at target tissue marker loci. One of these lung samples revealed only non-intended off-target signals for blood. The observed differences might be due to differences in sample collection during routine autopsy, technical differences due to the PCR cycler, and the threshold used for signal calling. Indicating the presence of additional tissue type and off-target unmethylation signals seems alleviated by applying more stringent hypomethylation thresholds. Therefore, the developed SNaPshot multiplex assays will be valuable for forensic investigators dealing with organ tissue identification, as well as for prosecutors and defense aiming to establish the circumstances that occurred at the crime scene.
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Affiliation(s)
- Bo Min Kim
- Department of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sang Un Park
- Department of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Laura Schmelzer
- Institute of Forensic Medicine, Medical Center -University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Soo-Bin Yang
- Department of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Soong Deok Lee
- Department of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea; Institute of Forensic and Anthropological Science, Seoul National University College of Medicine, Seoul, Korea
| | - Moon-Young Kim
- Laboratory of Forensic Medicine, Department of Anatomy and Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Jana Naue
- Institute of Forensic Medicine, Medical Center -University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
| | - Hwan Young Lee
- Department of Forensic Medicine, Seoul National University College of Medicine, Seoul, Korea; Institute of Forensic and Anthropological Science, Seoul National University College of Medicine, Seoul, Korea.
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6
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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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7
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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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8
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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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9
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Arsenault H, Kuffel A, Daeid NN, Gray A. Trace DNA and its persistence on various surfaces: A long term study investigating the influence of surface type and environmental conditions - Part one, metals. Forensic Sci Int Genet 2024; 70:103011. [PMID: 38324952 DOI: 10.1016/j.fsigen.2024.103011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/09/2024]
Abstract
It is imperative for proper evidence triage that forensic biologists understand what kind of results to expect from certain evidence types submitted for DNA analysis. The persistence of trace DNA has been insufficiently investigated and there is little data available pertaining to the persistence of DNA in different environmental conditions and on different materials. The goal of this study is to increase the available data on this topic which would, in turn, help forensic biologists manage expectations when submitting specific evidence types for DNA testing. The work presented herein is a large-scale persistence project aimed to identify trends in the persistence of trace DNA and indicate how different environmental storage conditions and target surface characteristics influence the persistence of cellular and cell free DNA (cfDNA) over time. To eliminate variation within the experiment we used a proxy DNA deposit consisting of a synthetic fingerprint solution, cellular DNA, and/or cfDNA. Samples were collected and analysed from 7 metals over the course of 1 year (27 time points) under 3 different environmental storage conditions. The results of this experiment show that metal type greatly influences DNA persistence. For instance, copper exhibited an expected poor DNA persistence (up to 4 h) which a purification step did not help increase the DNA yield. Alternatively, DNA can persist for up to a year on lead at levels potentially high enough to allow for forensic DNA testing. Additionally, this study showed that the sample storage environment had no impact on DNA persistence in most cases. When considering DNA type, cfDNA was shown to persist for longer than cellular DNA and persistence as a whole appears to be better when DNA is deposited as mixtures over when deposited alone. Unsurprisingly, it can be expected that DNA recovery rates from trace deposits will decrease over time. However, DNA decay is highly dependent on the metal surface and extremely variable at short time points but slightly less variable as time since deposition increases. This data is intended to add to our understanding of DNA persistence and the factors which affect it.
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Affiliation(s)
- Hilary Arsenault
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK.
| | - Agnieszka Kuffel
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
| | - Niamh Nic Daeid
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
| | - Alexander Gray
- Leverhulme Research Center for Forensic Science, University of Dundee, Smalls Wynd, Dundee DD1 4HN, UK
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10
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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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11
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Hughes DA, Szkuta B, van Oorschot RAH, Conlan XA. The impact of substrate characteristics on the collection and persistence of biological materials, and their implications for forensic casework. Forensic Sci Int 2024; 356:111951. [PMID: 38301431 DOI: 10.1016/j.forsciint.2024.111951] [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: 09/22/2023] [Revised: 01/14/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
This study assessed the level of nucleic acid persistence on the substrate pre-, and post-swabbing, in order to assess whether biological materials (touch, saliva, semen, and blood) are collected differently depending on the substrate characteristics. A total of 48 samples per deposit and substrate variety (n = 384) were assessed by tracking the persistence of nucleic acid using Diamond™ Nucleic Acid Dye (DD) staining and Polilight photography. The number of DD nucleic acid fluorescent complexes formed post-staining were counted (fluorescent count) and in conjunction with the fluorescence signal intensity (DD nucleic acid complex accumulation) used to estimate the level of nucleic acid persistence on substrates. Touch deposits have shown to be the most persistent deposit with strong adhesion capabilities on both substrate verities. Saliva displayed a higher persistence than semen and/or blood. Semen displayed a high collection efficiency as well as a high fluorescence signal intensity. Blood displayed a low persistence on both substrates with a superior collection efficiency that may also indicate a higher probability to become dislodged from surfaces given a particular activity. Our research has shown that the persistence and recovery of biological deposits is not only measurable but more importantly, may have the potential to be estimated, as such, may build an understanding that can provide valuable guidance for collection efficiency evaluations, and the assessing of the probability of particular profiles, given alternate propositions of means of transfer occurring.
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Affiliation(s)
- Deborah A Hughes
- Deakin University, School of Life and Environmental Sciences, Geelong, Australia; Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, Macleod, Australia
| | - Bianca Szkuta
- Deakin University, School of Life and Environmental Sciences, Geelong, Australia
| | - Roland A H van Oorschot
- Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, Macleod, Australia; School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Australia
| | - Xavier A Conlan
- Deakin University, School of Life and Environmental Sciences, Geelong, Australia.
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12
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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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13
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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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14
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Kubo S, Amai K, Tanaka J, Niimi H. One-tube, two-step isothermal amplification of histatin 3 mRNA for saliva screening. Forensic Sci Int 2023; 352:111847. [PMID: 37837846 DOI: 10.1016/j.forsciint.2023.111847] [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: 07/21/2023] [Accepted: 09/23/2023] [Indexed: 10/16/2023]
Abstract
Saliva samples are frequently collected at crime scenes. Salivary mRNA profiling, such as that of histatin 3 (HTN3), is a highly specific approach that overcomes the limitation of traditional amylase tests. However, typical mRNA detection methods based on reverse transcription PCR (RT-PCR) are time-consuming and labor-intensive. Here, we report a one-tube, two-step isothermal amplification assay for HTN3 mRNA, which enables rapid, simple, and sensitive screening of saliva. The first step is an RT-recombinase polymerase amplification (RT-RPA) assay at 42 °C for 20 min; the second step is a loop-mediated isothermal amplification (LAMP) assay at 65 °C for 30 min. The reactions can be performed in a closed tube, and the products are detected using real-time fluorescence analysis. The assay sensitivity was 0.5 µL of saliva samples. It also detected HTN3 mRNA in mixed and mock samples, demonstrating its applicability to actual forensic samples. These findings suggest that our strategy is promising for screening of saliva from forensic samples.
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Affiliation(s)
- Seiji Kubo
- Department of Clinical Laboratory and Molecular Pathology, Faculty of Medicine, Academic Assembly, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; Forensic Science Laboratory, Ishikawa Prefectural Police Headquarters, 1-1 Kuratsuki, Kanazawa 920-8553, Japan.
| | - Keito Amai
- Forensic Science Laboratory, Ishikawa Prefectural Police Headquarters, 1-1 Kuratsuki, Kanazawa 920-8553, Japan
| | - Jin Tanaka
- Forensic Science Laboratory, Ishikawa Prefectural Police Headquarters, 1-1 Kuratsuki, Kanazawa 920-8553, Japan
| | - Hideki Niimi
- Department of Clinical Laboratory and Molecular Pathology, Faculty of Medicine, Academic Assembly, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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15
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Nolan M, Handt O, Linacre A. Persistence of cellular material after exposure to water. J Forensic Sci 2023; 68:2128-2137. [PMID: 37356058 DOI: 10.1111/1556-4029.15316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/08/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
Disposing of items of forensic relevance in bodies of water is one countermeasure offenders can use to avoid detection. The impact of immersion in water has been explored for blood, saliva, and semen; however, few studies have assessed touch DNA. Here we report on the effect of exposure to water on the persistence of touch DNA over prolonged periods of time. To evaluate the persistence of cells from touch DNA, after water exposure, three substrates and two water types were tested: plastic, metal, and ceramic, submerged into seawater or tap water. Diamond™ Nucleic Acid Dye was used to stain cells deposited by touch. Cell counts before and after water exposure were compared to investigate cell loss over time, ranging from 6 hours to 5 days. A logarithmic increase in the percent of cells lost was observed over time when the data for substrate and water type conditions were combined. Substrate type influenced the persistence of cells, with the metal substrate retaining cells longer than plastic or ceramic. The influence of water type appeared dependent on the substrate, with varied cell persistence on metal whereas plastic and ceramic recorded similar cell loss over time between water types. The ability to visualize cells after exposure to water could assist in triaging evidence within operational forensic laboratories and allow for targeted sampling. This proof-of-concept study demonstrated that greater than 50% of cells can persist on various items submerged in aqueous environments for at least 5 days, highlighting the possibility for downstream DNA testing.
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Affiliation(s)
- Madison Nolan
- College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Oliva Handt
- College of Science and Engineering, Flinders University, Adelaide, Australia
- Forensic Science South Australia, Adelaide, Australia
| | - Adrian Linacre
- College of Science and Engineering, Flinders University, Adelaide, Australia
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16
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Żarczyńska M, Żarczyński P, Tomsia M. Nucleic Acids Persistence-Benefits and Limitations in Forensic Genetics. Genes (Basel) 2023; 14:1643. [PMID: 37628694 PMCID: PMC10454188 DOI: 10.3390/genes14081643] [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: 07/13/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
The analysis of genetic material may be the only way to identify an unknown person or solve a criminal case. Often, the conditions in which the genetic material was found determine the choice of the analytical method. Hence, it is extremely important to understand the influence of various factors, both external and internal, on genetic material. The review presents information on DNA and RNA persistence, depending on the chemical and physical factors affecting the genetic material integrity. One of the factors taken into account is the time elapsing to genetic material recovery. Temperature can both preserve the genetic material or lead to its rapid degradation. Radiation, aquatic environments, and various types of chemical and physical factors also affect the genetic material quality. The substances used during the forensic process, i.e., for biological trace visualization or maceration, are also discussed. Proper analysis of genetic material degradation can help determine the post-mortem interval (PMI) or time since deposition (TsD), which may play a key role in criminal cases.
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Affiliation(s)
- Małgorzata Żarczyńska
- School of Medicine in Katowice, Medical University of Silesia, 18 Medyków Street, 40-752 Katowice, Poland; (M.Ż.); (P.Ż.)
| | - Piotr Żarczyński
- School of Medicine in Katowice, Medical University of Silesia, 18 Medyków Street, 40-752 Katowice, Poland; (M.Ż.); (P.Ż.)
| | - Marcin Tomsia
- Department of Forensic Medicine and Forensic Toxicology, Medical University of Silesia, 18 Medyków Street, 40-752 Katowice, Poland
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17
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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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18
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Meijrink L, van der Scheer M, Kokshoorn B. Bloodstain pattern analysis & Bayes: A case report. Sci Justice 2023; 63:551-561. [PMID: 37453788 DOI: 10.1016/j.scijus.2023.06.005] [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: 12/22/2022] [Revised: 06/12/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
The findings from a bloodstain pattern analysis (BPA) may assist in formulating or falsifying scenarios that are considered in the investigative stages of a criminal investigation. When a case proceeds to trial the bloodstain pattern expert may be asked about the relevance of their findings given scenarios that are proposed by the prosecution and defense counsel. Such opinions provided by an expert are highly relevant to police investigation or legal proceedings, but the reasoning behind the opinion or implicit assumptions made by the expert may not be transparent. A proper framework for the evaluation of forensic findings has been developed since the late twentieth century, based on the hierarchy of propositions, Bayesian reasoning and a model for case assessment and interpretation. This framework, when implemented in casework, mitigates some of the risks of cognitive biases, and makes the reasoning and scientific basis for the opinion transparent. This framework is broadly used across forensic science disciplines. In this paper we describe its application to the field of BPA using a case example from the Netherlands Forensic Institute (NFI).
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Affiliation(s)
- Leon Meijrink
- Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497 GB The Hague, The Netherlands.
| | - Mikle van der Scheer
- Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497 GB The Hague, The Netherlands
| | - Bas Kokshoorn
- Netherlands Forensic Institute, Division of Biological Traces, Laan van Ypenburg 6, 2497 GB The Hague, The Netherlands; Amsterdam University of Applied Sciences, Faculty of Technology, Amsterdam, The Netherlands
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19
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Allard JE, Davidson G, Baird A, Boyce M, Jones S, Lewis J, Lowrie C, McBride BM. The relevance of false positive acid phosphatase reactions indicative of the presence of seminal fluid from oral and vaginal samples. Sci Justice 2023; 63:477-484. [PMID: 37453779 DOI: 10.1016/j.scijus.2023.04.010] [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: 03/27/2023] [Accepted: 04/22/2023] [Indexed: 07/18/2023]
Abstract
The Body Fluid Forum of the Association of Forensic Science Providers recognised concerns raised by forensic practitioners regarding the lack of data to inform on the incidence of significant AP (Acid Phosphatase) reactions from vaginal and oral samples, i.e. those which might be misinterpreted as indicating the presence of semen. This is particularly relevant in the light of appeal court rulings regarding the need for data to support evaluations. This paper presents collaborative data on the nature and incidence of AP reactions from vaginal and oral swabs provided by donors. The results demonstrate that caution is required with mid to strong purple AP reactions from direct testing of oral swabs and with mid purple reactions from vaginal swabs. The use of a Bayesian approach to assist with the provision of opinions regarding the presence of seminal fluid is highlighted.
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Affiliation(s)
- J E Allard
- Formerly of Forensic Science Service Ltd, 109 Lambeth Road, London SE1 7LP, United Kingdom.
| | - G Davidson
- Cellmark Forensic Services, Unit B1, Buckshaw Link, Ordnance Road, Buckshaw Village, Chorley, Lancashire PR7 7EL, United Kingdom.
| | - A Baird
- Formerly of Forensic Science Northern Ireland, 151 Belfast Road, Carrickfergus, Co. Antrim BT38 8PL, Northern Ireland
| | - M Boyce
- Formerly of Key Forensic Services, 207C Cavendish Place, Birchwood Park, Warrington WA3 6WU, United Kingdom
| | - S Jones
- SPA Forensic Services, Aberdeen, Nelson Street, Aberdeen AB24 5EQ, United Kingdom.
| | - J Lewis
- Formerly of Cellmark Forensic Services, 16 Blacklands Way, Abingdon Business Park, Abingdon, Oxfordshire OX14 1DY, United Kingdom
| | - C Lowrie
- Formerly of Eurofins Forensic Services, Building 3, Drayton Manor Business Park, Tamworth, Staffordshire B78 3GL, United Kingdom
| | - B M McBride
- Department of Justice and Equality, Forensic Science Ireland, Garda Headquarters, Phoenix Park, Dublin 8, Ireland.
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20
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Taylor D, Abarno D. A lights-out forensic DNA analysis workflow for no-suspect crime. Forensic Sci Int Genet 2023; 66:102907. [PMID: 37379740 DOI: 10.1016/j.fsigen.2023.102907] [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: 04/13/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 06/30/2023]
Abstract
An automated system of DNA profile processing (termed a 'lights-out' workflow) was trialled for no-suspect cases over a three-month period at Forensic Science SA (FSSA). The lights-out workflow utilised automated DNA profile reading using the neural network reading feature in FaSTR™ DNA with no analytical threshold. The profile information from FaSTR™ DNA was then processed in STRmix™ using a top-down analysis and automatically compared to a de-identified South Australian searchable DNA database. Computer scripts were used to generate link reports and upload reports and these were compared to the links and uploads that were obtained for the cases during their standard processing within the laboratory. The results of the lights-out workflow was an increase in both uploads and links compared to the standard workflow, with minimal adventitious links or erroneous uploads. Overall, the proof-of-concept study shows the potential for using automated DNA profile reading and top-down analysis to improve workflow efficiency in a no-suspect workflow.
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Affiliation(s)
- Duncan Taylor
- Forensic Science SA, Adelaide, Australia; Flinders University, Adelaide, Australia.
| | - Damien Abarno
- Forensic Science SA, Adelaide, Australia; Flinders University, Adelaide, Australia
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21
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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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22
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Arsenault H, Nic Daeid N, Gray A. A synthetic fingerprint solution and its importance in DNA transfer, persistence and recovery studies. Forensic Sci Int Synerg 2023; 6:100330. [PMID: 37249970 PMCID: PMC10209804 DOI: 10.1016/j.fsisyn.2023.100330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/20/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023]
Abstract
A review of the literature on DNA transfer and persistence highlights many difficulties that are encountered when conducting research of this nature. One of the main problems highlighted repeatedly in the literature is the prevalence of inherent uncontrolled variation that accompany these studies, and in turn, the results obtained. This work aims to decrease the amount of intrinsic variability associated with DNA transfer and persistence experiments using a realistic proxy solution which is adaptable, of known composition, reproducible, and capable of being standardised. This proxy is composed of three parts: a synthetic fingerprint solution, cellular DNA, and cell free DNA. In this proof-of-concept study the proxy was tested with a small-scale DNA transfer and recovery experiment and the data obtained suggests that the use of a solution that mimics real fingerprint secretions, over an alternative (such as buffer or a body fluid), is important when working with non-donor provided trace DNA samples. This is because the DNA deposit solution likely impacts the transfer of DNA from fingers/hands to a surface as well as the ability to recover the biological material once deposited.
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23
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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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24
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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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Kokshoorn B, Luijsterburg M. Reporting on forensic biology findings given activity level issues in the Netherlands. Forensic Sci Int 2023; 343:111545. [PMID: 36634430 DOI: 10.1016/j.forsciint.2022.111545] [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: 09/01/2022] [Revised: 11/05/2022] [Accepted: 12/22/2022] [Indexed: 12/31/2022]
Abstract
There appears to be some hesitation within the forensic biology community to formally evaluate and report on findings given activity level propositions. This hesitance in part stems from concerns about the lack of relevant data on the dynamics of biological traces and doubt about the relevance of such expert opinions to the trier of fact. At the Netherlands Forensic Institute formal evaluative opinions on the probability of case findings given propositions at the activity level are provided since 2013, if requested by a mandating authority. In this study we share the results from a retrospective analysis of 74 of such requests. We explore which party initiates requests, the types of cases that are submitted, the sources of data being used to assign probabilities to DNA transfer, persistence, prevalence and recovery (TPPR) events, the conclusions that were drawn by the scientists, and how the conclusions were used by the courts. This retrospective analysis of cases demonstrates that published sources of data are generally available and can be used to address DNA TPPR events in most cases, although significant gaps still remain. The study furthermore shows that reporting on forensic biology findings given activity level propositions has been generally accepted by the district and appeal courts, as well as the other parties in the criminal justice system in the Netherlands.
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Affiliation(s)
- Bas Kokshoorn
- Netherlands Forensic Institute, P.O.Box 24044, 2490 AA The Hague, the Netherlands; Forensic Trace Dynamics, Faculty of Technology, Amsterdam University of Applied Sciences, Amsterdam, the Netherlands.
| | - Maartje Luijsterburg
- Netherlands Forensic Institute, P.O.Box 24044, 2490 AA The Hague, the Netherlands
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26
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Mercer C, Taylor D, Henry J, Linacre A. DNA accumulation and transfer within an operational forensic exhibit storeroom. Forensic Sci Int Genet 2023; 62:102799. [PMID: 36274409 DOI: 10.1016/j.fsigen.2022.102799] [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: 06/15/2022] [Revised: 09/09/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022]
Abstract
The increased sensitivity of current DNA profiling technologies allows the detection of trace amounts of DNA. With these advancements, there is an increased probability of detecting trace levels of DNA from contamination. Studies which investigate the accumulation and transfer of DNA within forensic laboratories provide insight into the possible mechanisms which may result in the contamination of exhibits. To gain a greater understanding of the level of DNA transfer between exhibit packaging and forensic workspaces, the accumulation of DNA within an operational forensic exhibit storeroom was investigated. Samples were collected from previously cleaned forensic exhibit storeroom shelves at various time points over a 14-week period. To determine the source of accumulating DNA, profiles generated from shelf samples were compared to the laboratory staff elimination database and the profiles generated from exhibits stored on each of the shelves sampled over the course of the study. Additionally, all samples were compared using STRmix™ mixture-to-mixture profile analysis, to identify the presence of common non-staff DNA donors and DNA from exhibits stored on the shelves sampled. As sampling time intervals increased, there was a significant increase in DNA quantity (ng) and number of profile contributors. The shelf height was also observed to influence the number of profile contributors, with higher numbers of contributors being found on lower shelves. DNA profiles generated from the shelf samples were matched to DNA from forensic staff members who enter the storeroom and police employees, who do not enter the storeroom. There were three instances where a common DNA profile contributor was identified between a shelf sample and the profile generated from an exhibit.This study provides insight into whether current exhibit storage procedures are still adequate given the highly sensitive DNA profiling systems currently used.
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Affiliation(s)
- Claire Mercer
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia.
| | - Duncan Taylor
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia; Forensic Science SA, GPO Box 2790, Adelaide 5001, Australia
| | - Julianne Henry
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia; Forensic Science SA, GPO Box 2790, Adelaide 5001, Australia
| | - Adrian Linacre
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
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27
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Carson S, Volgin L, Abarno D, Taylor D. The potential for investigator-mediated contamination to occur during routine search activities. Forensic Sci Med Pathol 2022; 18:299-310. [PMID: 35254643 DOI: 10.1007/s12024-022-00465-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2022] [Indexed: 12/14/2022]
Abstract
The sensitivity and discrimination power of modern DNA profiling systems means that very small amounts of DNA from an individual can be detected on an item leading to large inclusionary statistics for that person. The sensitivity of these systems has significant benefits in the investigation of crime but also can be highly sensitive to contamination of exhibits or crime scenes. It becomes critical to distinguish between deposition during commission of a crime or deposition via some other method unrelated to the crime. This study investigates methodologies used in crime scene examination and the potential for them to cause non-crime-related transfer of DNA. Factors assessed include the source of DNA, the handling time, the amount of movement during contact, and the substrate type. The amount of movement and the number of transfer steps are the most critical in determining whether, and how much, DNA is transferred. This study provides information for crime scene examiners and also scientists assessing transfer scenarios.
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Affiliation(s)
- Sasha Carson
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Luke Volgin
- Forensic Science SA, PO Box 2790, Adelaide, SA, 5000, Australia
| | - Damien Abarno
- Forensic Science SA, PO Box 2790, Adelaide, SA, 5000, Australia
| | - Duncan Taylor
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia. .,Forensic Science SA, PO Box 2790, Adelaide, SA, 5000, Australia.
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28
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Gill P, Bleka Ø, Fonneløp AE. Limitations of qPCR to estimate DNA quantity: An RFU method to facilitate inter-laboratory comparisons for activity level, and general applicability. Forensic Sci Int Genet 2022; 61:102777. [DOI: 10.1016/j.fsigen.2022.102777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/08/2022] [Accepted: 09/16/2022] [Indexed: 11/25/2022]
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29
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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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30
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Adamowicz MS, Rambo TN, Clarke JL. Internal Validation of MaSTR™ Probabilistic Genotyping Software for the Interpretation of 2–5 Person Mixed DNA Profiles. Genes (Basel) 2022; 13:genes13081429. [PMID: 36011340 PMCID: PMC9408203 DOI: 10.3390/genes13081429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/07/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Mixed human deoxyribonucleic acid (DNA) samples present one of the most challenging pieces of evidence that a forensic analyst can encounter. When multiple contributors, stochastic amplification, and allele drop-out further complicate the mixture profile, interpretation by hand becomes unreliable and statistical analysis problematic. Probabilistic genotyping software has provided a tool to address complex mixture interpretation and provide likelihood ratios for defined sets of propositions. The MaSTR™ software is a fully continuous probabilistic system that considers a wide range of STR profile data to provide likelihood ratios on DNA mixtures. Mixtures with two to five contributors and a range of component ratios and allele peak heights were created to test the validity of MaSTR™ with data similar to real casework. Over 280 different mixed DNA profiles were used to perform more than 2600 analyses using different sets of propositions and numbers of contributors. The results of the analyses demonstrated that MaSTR™ provided accurate and precise statistical data on DNA mixtures with up to five contributors, including minor contributors with stochastic amplification effects. Tests for both Type I and Type II errors were performed. The findings in this study support that MaSTR™ is a robust tool that meets the current standards for probabilistic genotyping.
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31
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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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32
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Atkinson K, Arsenault H, Taylor C, Volgin L, Millman J. Transfer and persistence of DNA on items routinely encountered in forensic casework following habitual and short-duration one-time use. Forensic Sci Int Genet 2022; 60:102737. [PMID: 35753208 DOI: 10.1016/j.fsigen.2022.102737] [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: 01/12/2022] [Revised: 05/19/2022] [Accepted: 06/06/2022] [Indexed: 11/04/2022]
Abstract
Empirical data obtained from controlled experiments is necessary to ensure that sound expert opinion evidence is provided regarding transfer and persistence of DNA in criminal proceedings. Knowledge in this area is also required at the outset of criminal investigations, to ensure that the proposed examinations can assist with answering questions that are relevant to forensic investigations. This study aimed to provide such data by examining the relative and absolute quantities of DNA deposited on items that are routinely submitted to the forensic laboratory by a habitual user, defined as someone who used it for ~1 week, and a subsequent one-time user. We found that the quantity of DNA deposited on routine household items spanned a broad range. The habitual user's DNA was detected on most items as the major donor, regardless of whether it was subsequently handled by another person for a short period of time. The one-time, short duration, user's DNA was detected on approximately two thirds of the items, albeit typically at quantities lower than the habitual user. Most of the household items we examined also had detectable DNA deposits from at least one other, unknown individual, typically in low quantities. Attempts to clean non-porous items with readily available household cleaners were partially effective but failed to completely eliminate detectable DNA from a habitual user in most cases.
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Affiliation(s)
- Kirsty Atkinson
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada
| | - Hilary Arsenault
- Centre of Forensic Science, Royal College Building, University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, United Kingdom
| | - Christian Taylor
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada
| | - Luke Volgin
- Forensic Science SA, PO Box 2790, Adelaide, SA 5000, Australia
| | - Jonathan Millman
- Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, Ontario M3M 0B1, Canada.
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33
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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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34
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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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35
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Mögliche indirekte Übertragung von DNA-Spuren. Rechtsmedizin (Berl) 2022. [DOI: 10.1007/s00194-022-00576-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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36
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Dørum G, Bleka Ø, Gill P, Haas C. Source level interpretation of mixed biological stains using coding region SNPs. Forensic Sci Int Genet 2022; 59:102685. [DOI: 10.1016/j.fsigen.2022.102685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 11/28/2022]
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37
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Fantinato C, Gill P, Fonneløp AE. Non-self DNA on the neck: a 24 hours time-course study. Forensic Sci Int Genet 2022; 57:102661. [DOI: 10.1016/j.fsigen.2022.102661] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/04/2022]
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38
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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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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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40
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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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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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Oosthuizen T, Howes LM. The development of forensic DNA analysis: New debates on the issue of fundamental human rights. Forensic Sci Int Genet 2021; 56:102606. [PMID: 34710822 DOI: 10.1016/j.fsigen.2021.102606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 08/28/2021] [Accepted: 10/12/2021] [Indexed: 12/14/2022]
Abstract
Before the advent of forensic DNA profiling, forensic techniques such as fingerprint examination and blood type comparison were used in the identification of suspects. DNA profiling has since become the gold standard of forensic science, and forensic DNA analysis techniques continue to evolve. Recent developments such as familial searching and phenotyping have raised ethical questions and concerns reflecting those expressed in the late 1980s when forensic DNA analysis was first introduced. At that time, attempts to use DNA evidence in criminal trials were met with challenges to its evidential value and admissibility. A common concern was whether the probative value of the evidence would outweigh its potentially prejudicial effect. This gave rise to a complex three-way debate, which revolved around first, the admissibility of the scientific principles in criminal courts; second, the scientific process involved in analysing DNA samples; and third, the impact that forensic DNA analysis may have on fundamental human rights. Ultimately, debates about the scientific process and the admissibility of such evidence in criminal trials overshadowed the debate about potential infringements of fundamental human rights. This resulted in a lack of critical discussion around the erosion of civil liberties through the use of scientific technologies. This paper revisits the early debates on the development of forensic DNA analysis. It draws parallels with current developments and analyses the potential for current and future human rights infringements, highlighting that the libertarian model offers a necessary counterbalance to the other arguments, due to its concern for maintaining fundamental rights.
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Affiliation(s)
- Tersia Oosthuizen
- University of Tasmania, Law and Education, College of Arts, School of Social Sciences, Private Bag 22, Hobart 7001, Tasmania, Australia.
| | - Loene M Howes
- University of Tasmania, Law and Education, College of Arts, School of Social Sciences, Private Bag 22, Hobart 7001, Tasmania, Australia.
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43
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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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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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Puliatti L, Handt O, Taylor D. The level of DNA an individual transfers to untouched items in their immediate surroundings. Forensic Sci Int Genet 2021; 54:102561. [PMID: 34303991 DOI: 10.1016/j.fsigen.2021.102561] [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: 05/19/2021] [Revised: 06/24/2021] [Accepted: 07/03/2021] [Indexed: 12/01/2022]
Abstract
Due to advances in DNA profiling sensitivity as well as the implementation of various types of software to analyse these profiles, forensic biologists can provide opinions about results generated from very low levels of template DNA. The ability to obtain DNA profiles from such 'trace' DNA brings into question the mechanisms of transfer which led to it being deposited. This study investigates the level of DNA that is deposited by an individual to their work environment. DNA collection plates were placed at distances from 0.5 to 5 m from individuals' office desks and left for 1 day to 6 weeks before being swabbed and profiled with GlobalFiler. The results from this study indicate that an individual can deposit DNA in areas they were present, even if surfaces and/or objects were not directly contacted and even after only one day. Distance from a person, the length of time and the person themselves all play a role in the quantity of DNA that is deposited to one's surroundings.
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Affiliation(s)
- Lucas Puliatti
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Oliva Handt
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Forensic Science SA, PO Box 2790, Adelaide, South Australia 5000, Australia
| | - Duncan Taylor
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Forensic Science SA, PO Box 2790, Adelaide, South Australia 5000, Australia.
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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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47
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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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An LR framework incorporating sensitivity analysis to model multiple direct and secondary transfer events on skin surface. Forensic Sci Int Genet 2021; 53:102509. [PMID: 33930816 DOI: 10.1016/j.fsigen.2021.102509] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 03/16/2021] [Accepted: 03/20/2021] [Indexed: 01/19/2023]
Abstract
Bayesian logistic regression is used to model the probability of DNA recovery following direct and secondary transfer and persistence over a 24 h period between deposition and sample collection. Sub-source level likelihood ratios provided the raw data for activity-level analysis. Probabilities of secondary transfer are typically low, and there are challenges with small data-sets with low numbers of positive observations. However, the persistence of DNA over time can be modelled by a single logistic regression for both direct and secondary transfer, except that the time since deposition must be compensated by an offset value for the latter. This simplifies the analysis. Probabilities are used to inform an activity-level Bayesian Network that takes account of alternative propositions e.g. time of assault and time of social activities. The model is extended in order to take account of multiple contacts between person of interest and 'victim'. Variables taken into account include probabilities of direct and secondary transfer, along with background DNA from unknown individuals. The logistic regression analysis is Bayesian - for each analysis, 4000 separate simulations were carried out. Quantile assignments enable calculation of a plausible range of probabilities and sensitivity analysis is used to describe the corresponding variation of LRs that occur when modelled by the Bayesian network. It is noted that there is need for consistent experimental design, and analysis, to facilitate inter-laboratory comparisons. Appropriate recommendations are made. The open-source program written in R-code ALTRaP (Activity Level, Transfer, Recovery and Persistence) enables analysis of complex multiple transfer propositions that are commonplace in cases-work e.g. between those who cohabit. A number of case examples are provided. ALTRaP can be used to replicate the results and can easily be modified to incorporate different sets of data and variables.
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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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50
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Rodriguez JJRB, Laude RP, De Ungria MCA. An integrated system for forensic DNA testing of sexual assault cases in the Philippines. Forensic Sci Int Synerg 2021; 3:100133. [PMID: 33554100 PMCID: PMC7848663 DOI: 10.1016/j.fsisyn.2021.100133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/15/2020] [Accepted: 01/04/2021] [Indexed: 11/20/2022]
Abstract
In the Philippines, more than 7000 cases of sexual assault are reported annually. DNA technology is a powerful tool in identifying assailants. However, it is not routinely used in sexual assault investigations due to insufficient government support to cover the high cost of DNA testing and the absence of a national system for sample collection, handling, storage, and DNA testing of biological evidence. In itself, the nature of sexual assault samples containing DNA mixtures presents challenges to laboratory methods and interpretation of results. The sample recovered from the victim may only contain trace amounts of the assailant’s DNA, may have degraded due to prolonged storage in ambient conditions which is warm and humid in the tropics, or contaminated with inhibitors, such as in anal swabs. Hence, a closer evaluation of the processes of evidence collection and DNA testing is needed to increase the likelihood of success in generating conclusive results. In this paper, we propose an integrated system for DNA testing of biological samples collected from sexual assault victims considering the limitations of resources and the prevailing warm climate. Recommendations in this work should provide basis for formulating national guidelines for DNA analysis in aid of criminal investigations. The proposed scheme can be adopted by forensic DNA laboratories in the Philippines and in other countries facing similar challenges.
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Affiliation(s)
- Jae Joseph Russell B. Rodriguez
- DNA Analysis Laboratory, Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, 1101, Philippines
- Genetics and Molecular Biology Division, Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines Los Baños, Laguna, 4031, Philippines
| | - Rita P. Laude
- Genetics and Molecular Biology Division, Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines Los Baños, Laguna, 4031, Philippines
| | - Maria Corazon A. De Ungria
- DNA Analysis Laboratory, Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, 1101, Philippines
- Corresponding author.
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