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Fantinato C, Gill P, Fonneløp AE. Investigative use of human environmental DNA in forensic genetics. Forensic Sci Int Genet 2024; 70:103021. [PMID: 38335776 DOI: 10.1016/j.fsigen.2024.103021] [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: 11/15/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
Individuals leave behind traces of their DNA wherever they go. DNA can be transferred to surfaces and items upon touch, can be released into the air, and may be deposited in indoor dust. The mere presence of individuals in a location is sufficient to facilitate either direct or indirect DNA transfer into the surrounding environment. In this study, we analyzed samples recovered from commonly touched surfaces such as light switches and door handles in an office environment. We evaluated two different methods to isolate DNA and co-extract DNA and RNA from the samples. DNA profiles were compared to the references of the inhabitants of the different locations and were analyzed taking into consideration the type of sampled surface, sampling location and information about the activities in a room during the sampling day. Results from DNA samples collected from surfaces were also compared to those from air and dust samples collected in parallel from the same areas. We characterized the amount and composition of DNA found on various surfaces and showed that surface DNA sampling can be used to detect occupants of a location. The results also indicate that combining information from environmental samples collected from different DNA sources can improve our understanding of DNA transfer events in an indoor setting. This study further demonstrates the potential of human environmental DNA as an investigative tool in forensic genetics.
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Affiliation(s)
- 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.
| | - 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
| | - 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
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2
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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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3
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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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4
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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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5
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McCrane SM, Mulligan CJ. An innovative transfer DNA experimental design and qPCR assay to identify primary, secondary, and tertiary DNA transfer. J Forensic Sci 2024; 69:618-630. [PMID: 38108622 DOI: 10.1111/1556-4029.15444] [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: 08/13/2023] [Revised: 11/09/2023] [Accepted: 11/27/2023] [Indexed: 12/19/2023]
Abstract
"Touch DNA" is a form of trace DNA that is presumed to be deposited when an individual touches something and leaves behind DNA-containing skin cells, sweat, or other fluids. While touch DNA is often the result of direct contact (i.e., primary transfer), it can also be indirectly transferred between surfaces or individuals (e.g., secondary or tertiary transfer). Even experts cannot distinguish between different types of transfer and do not fully understand which variables affect direct versus indirect transfer or how often each type of transfer occurs. In this study, we utilize an innovative protocol that combines a paired male and female transfer DNA experimental design with an Amelogenin qPCR assay to generate data on primary, secondary, and tertiary DNA transfer. We report frequencies of indirect DNA transfer and also investigate the potential effects of participant age, self-identified ethnicity, and skin conditions on DNA transfer. Out of 22 experimental trials, we detected primary transfer (male + female) in 71% of trials, secondary DNA transfer in 50% of trials, and tertiary DNA transfer in 27% of trials. No significant associations were found between primary DNA transfer and age, self-identified ancestry, or skin conditions, however, all individuals with sloughing skin conditions demonstrated primary DNA transfer and we suggest this variable be explored in larger samples. These results contribute to a better understanding of the conditions under which secondary and tertiary DNA transfer occurs and can be used to propose realistic DNA transfer scenarios in court cases.
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Affiliation(s)
- Samantha M McCrane
- Anthropology, University of New Hampshire, Durham, New Hampshire, USA
- Anthropology, University of Florida, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
| | - Connie J Mulligan
- Anthropology, University of Florida, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
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6
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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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7
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Sessa F, Pomara C, Esposito M, Grassi P, Cocimano G, Salerno M. Indirect DNA Transfer and Forensic Implications: A Literature Review. Genes (Basel) 2023; 14:2153. [PMID: 38136975 PMCID: PMC10742555 DOI: 10.3390/genes14122153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Progress in DNA profiling techniques has made it possible to detect even the minimum amount of DNA at a crime scene (i.e., a complete DNA profile can be produced using as little as 100 pg of DNA, equivalent to only 15-20 human cells), leading to new defense strategies. While the evidence of a DNA trace is seldom challenged in court by a defendant's legal team, concerns are often raised about how the DNA was transferred to the location of the crime. This review aims to provide an up-to-date overview of the experimental work carried out focusing on indirect DNA transfer, analyzing each selected paper, the experimental method, the sampling technique, the extraction protocol, and the main results. Scopus and Web of Science databases were used as the search engines, including 49 papers. Based on the results of this review, one of the factors that influence secondary transfer is the amount of DNA shed by different individuals. Another factor is the type and duration of contact between individuals or objects (generally, more intimate or prolonged contact results in more DNA transfer). A third factor is the nature and quality of the DNA source. However, there are exceptions and variations depending on individual characteristics and environmental conditions. Considering that secondary transfer depends on multiple factors that interact with each other in unpredictable ways, it should be considered a complex and dynamic phenomenon that can affect forensic investigation in various ways, for example, placing a subject at a crime scene who has never been there. Correct methods and protocols are required to detect and prevent secondary transfer from compromising forensic evidence, as well as the correct interpretation through Bayesian networks. In this context, the definition of well-designed experimental studies combined with the use of new forensic techniques could improve our knowledge in this challenging field, reinforcing the value of DNA evidence in criminal trials.
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Affiliation(s)
- Francesco Sessa
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
| | - Cristoforo Pomara
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
| | | | - Patrizia Grassi
- “Vittorio Emanuele” Hospital, University of Catania, 95121 Catania, Italy;
| | - Giuseppe Cocimano
- Department of Mental and Physical Health and Preventive Medicine, University of Campania “Vanvitelli”, 80121 Napoli, Italy;
| | - Monica Salerno
- Department of Medical, Surgical and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95121 Catania, Italy; (C.P.); (M.S.)
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8
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Fantinato C, Fonneløp AE, Bleka Ø, Vigeland MD, Gill P. The invisible witness: air and dust as DNA evidence of human occupancy in indoor premises. Sci Rep 2023; 13:19059. [PMID: 37925517 PMCID: PMC10625553 DOI: 10.1038/s41598-023-46151-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023] Open
Abstract
Humans constantly shed deoxyribonucleic acid (DNA) into the surrounding environment. This DNA may either remain suspended in the air or it settles onto surfaces as indoor dust. In this study, we explored the potential use of human DNA recovered from air and dust to investigate crimes where there are no visible traces available-for example, from a recently vacated drugs factory where multiple workers had been present. Samples were collected from three indoor locations (offices, meeting rooms and laboratories) characterized by different occupancy types and cleaning regimes. The resultant DNA profiles were compared with the reference profiles of 55 occupants of the premises. Our findings showed that indoor dust samples are rich sources of DNA and provide an historical record of occupants within the specific locality of collection. Detectable levels of DNA were also observed in air and dust samples from ultra-clean forensic laboratories which can potentially contaminate casework samples. We provide a Bayesian statistical model to estimate the minimum number of dust samples needed to detect all inhabitants of a location. The results of this study suggest that air and dust could become novel sources of DNA evidence to identify current and past occupants of a crime scene.
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Affiliation(s)
- Chiara Fantinato
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway.
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Ane Elida Fonneløp
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Øyvind Bleka
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
| | | | - Peter Gill
- Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway
- Department of Forensic Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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9
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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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10
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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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11
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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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12
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DNA deposited in whole thumbprints: a reproducibility study. Forensic Sci Int Genet 2022; 58:102683. [DOI: 10.1016/j.fsigen.2022.102683] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 01/27/2023]
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13
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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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14
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Jansson L, Swensson M, Gifvars E, Hedell R, Forsberg C, Ansell R, Hedman J. Individual shedder status and the origin of touch DNA. Forensic Sci Int Genet 2021; 56:102626. [PMID: 34781198 DOI: 10.1016/j.fsigen.2021.102626] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022]
Abstract
Due to improved laboratory techniques, touched surfaces and items are increasingly employed as sources of forensic DNA evidence. This has urged a need to better understand the mechanisms of DNA transfer between individuals. Shedder status (i.e. the propensity to leave DNA behind) has been identified as one major factor regulating DNA transfer. It is known that some individuals tend to shed more DNA than others, but the mechanisms behind shedder status are largely unknown. By comparing the amounts of DNA deposited from active hands (i.e. used "as usual") and inactive hands (i.e. not allowed to touch anything), we show that some of the self-DNA deposited from hands is likely to have accumulated on hands from other parts of the body or previously handled items (active hands: 2.1 ± 2.7 ng, inactive hands: 0.83 ± 1.1 ng, paired t-test: p = 0.014, n = 27 pairs of hands). Further investigation showed that individual levels of deposited DNA are highly associated with the level of DNA accumulation on the skin of the face (Pearson's correlation: r = 0.90, p < 0.00001 and Spearman's ranked correlation: rs = 0.56, p = 0.0016, n = 29). We hypothesized that individual differences in sebum secretion levels could influence the amount of DNA accumulation in facial areas, but no such correlation was seen (Pearson's correlation: r = - 0.13, p = 0.66, n = 14). Neither was there any correlation between DNA levels on hands or forehead and the time since hand or face wash. We propose that the amount of self-DNA deposited from hands is highly influenced by the individual levels of accumulated facial DNA, and that cells/DNA is often transferred to hands by touching or rubbing one's face.
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Affiliation(s)
- Linda Jansson
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Marie Swensson
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Emma Gifvars
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Ronny Hedell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden
| | | | - Ricky Ansell
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Department of Physics, Chemistry and Biology, IFM, Linköping University, Linköping, Sweden
| | - Johannes Hedman
- National Forensic Centre, Swedish Police Authority, Linköping, Sweden; Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
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