The complexities of DNA transfer during a social setting

Goray, Mariya; Oorschot, Roland A.H. van

doi:10.1016/j.legalmed.2014.10.003

Cited by 74 publications

(47 citation statements)

References 28 publications

(34 reference statements)

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“…Every one of the aggressors was touching the clothes of every one of the victims at two different days, resulting in a total of 72 samples, half of them sampled by wet swabbing, the other half by DPL. Almost all samples showed additional alleles from persons not participating in the experiments, as expected from the literature [20]. Since we could not detect any profile from the negative controls, we consider a contamination from the films unlikely, even though they are not manufactured for DNA collection purpose.…”

Section: / 19supporting

confidence: 71%

Electrostatic sampling of trace DNA from clothing

2016

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During acts of physical aggression, offenders frequently come into contact with clothes of the victim, thereby leaving traces of DNA-bearing biological material on the garments. Since tape-lifting and swabbing, the currently established methods for non-destructive trace DNA sampling from clothing, both have their shortcomings in collection efficiency and handling, we thought about a new collection method for these challenging samples. Testing two readily available electrostatic devices for their potential to sample biological material from garments made of different fabrics, we found one of them, the electrostatic dust print lifter (DPL), to perform comparable to well-established sampling with wet cotton swabs. In simulated aggression scenarios, we had the same success rate for the establishment of single aggressor profiles, suitable for database submission, with both the DPL and wet swabbing. However, we lost a substantial amount of information with electrostatic sampling, since almost no mixed aggressorvictim profiles suitable for database entry could be established, compared to conventional swabbing. This study serves as a proof of principle for electrostatic DNA sampling from items of clothing. The technique still requires optimization before it might be used in real casework. But we are confident that in the future it could be an efficient and convenient contribution to the toolbox of forensic practitioners.

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Section: / 19supporting

confidence: 71%

Electrostatic sampling of trace DNA from clothing

2016

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“…Detection of indirectly-transferred unknown DNA alongside expected DNA from the donor has been repeatedly reported, commonly at ≤10% of the profiles obtained, by studies involving handling or wearing of items and DNA profiling using the more sensitive kits [4,10,11,15,16,[25][26][27][28]. It is proposed that hands acquire such nondonor DNA via everyday activities that involve touching other people and other items that have been previously handled [10,16,20,27,28].…”

Section: Detection Of Indirectly-transferred Unknown Dnamentioning

confidence: 99%

“…Such indirect DNA transfer was initially identified in 1997 [2], and although there was some debate in the literature over the years that followed regarding the existence of indirect transfer and its relevance to casework, indirect transfer has been repeatedly demonstrated by empirical research and must be considered in the evaluation of trace DNA [3]. More recently, indirectlytransferred DNA has been observed in mock social settings [4] and stabbing simulations [5], and has been a key consideration in several high profile criminal cases, such as R v Reed & Reed [6], Fitzgerald v The Queen [7] and the miscarriages of justice of Amanda Knox and Raffaele Sollecito [8]. Furthermore, given that DNA can persist on surfaces for a number of days or weeks depending on the environmental conditions [9] and on objects after use by a subsequent person [10][11][12], persistence of both directly and indirectly transferred DNA also needs to be considered in the evaluation of trace DNA in casework.…”

Section: Introductionmentioning

confidence: 99%

Trace DNA evidence dynamics: An investigation into the deposition and persistence of directly- and indirectly-transferred DNA on regularly-used knives

Meakin¹,

Butcher²,

Oorschot

et al. 2017

Forensic Science International: Genetics

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Empirical data on the transfer and persistence of trace DNA are crucial to the evaluation of forensic DNA evidence. This evaluation can be complicated by the occurrence of indirect DNA transfer; the possibility of which is well established, but research into such transfer is often focussed on unrealistic situations, e.g. handling of DNA-free items after participants have shaken hands for 1-2min. To simulate more realistic scenarios, this study investigated the deposition and persistence of both directly- and indirectly-transferred DNA on knives that had been artificially set up as 'regularly-used'. Each knife was handled in a prescribed manner by a specific participant over two consecutive days to simulate regular use. Each participant then shook hands for 10s with a fellow volunteer and immediately stabbed one of their knives into a foam block repeatedly for 60s. DNA was recovered by mini-taping from triplicate sets of knife handles from four pairings of volunteers after regular use, and at one hour, one day and one week after the handshaking and stabbing events. Total amounts of DNA recovered from the knives, regularly used by a single person, varied among individuals; one volunteer consistently deposited significantly greater amounts than the others, whilst another volunteer did not always leave complete profiles. DNA attributed to the regular user persisted for at least a week, declining with increasing time between DNA deposition and recovery. Non-donor DNA was co-deposited at <5% of the profiles recovered, except for one volunteer, who consistently left DNA from their romantic partner on their knives at ∼25% and ∼11% of the profiles before and after the handshaking and stabbing events, respectively. In three pairings of volunteers, after the handshaking and stabbing events, alleles that could be attributed to the respective handshakers' profiles were detected as partial minor profiles, equating to ∼10% of the profiles recovered. For the fourth pairing of volunteers, only complete single-source DNA profiles matching the regular user's profile were recovered. However, it is important to note that, when indirectly-transferred handshaker DNA was detected, it declined with increasing time between DNA deposition and recovery. These data provide an initial insight into the detection and persistence of directly- and indirectly-transferred DNA that extend the data already available on forensic DNA transfer. The results herein suggest that the sooner an item is sampled after an offence has occurred, the greater the chance of recovering indirectly-transferred DNA, which has implications for forensic reconstructions.

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“…Further, Cale et al (1) posit that the transfer of DNA through an intermediary has not been systematically evaluated with current technology. Studies have provided empirical evidence of secondary (and further, including tertiary and quaternary) transfer (9,10,16,27), have investigated variables that may affect the transfer and subsequent detection of touch DNA (7,8,13,18,20,(22)(23)(24)28,29), have provided casework relevant examples and simulations to model the possible effect of transfer on conclusions (9)(10)(11)14,16,17,21,(30)(31)(32), and have provided statistical models to evaluate the possibility of transfer (33)(34)(35). Such studies have been conducted with various autosomal STR methods employed in forensic biology, including the current sensitive technologies, and, more recently, with alternate methods such as mRNA profiling (18,21).…”

Section: Sirmentioning

confidence: 99%