An RNA Expression Method for Aging Forensic Hair Samples

Hampson, Clint; Louhelainen, Jari; McColl, Suzzanne M.

doi:10.1111/j.1556-4029.2010.01641.x

Cited by 19 publications

(10 citation statements)

References 15 publications

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“…Hampson et al found changes in 18S after 45 days. 25 The differences in stability may be because Anderson et al kept their samples in a temperature-(25 C) and humidity-(50%) controlled chamber, while Hampson et al did not control conditions. We also used uncontrolled conditions, leaving samples at room temperature and room humidity, and with daylight.…”

Section: Stability Of 18s and B-actinmentioning

confidence: 97%

Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

Kong²,

2013

Journal of Forensic and Legal Medicine

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Section: Stability Of 18s and B-actinmentioning

confidence: 97%

Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

Kong²,

2013

Journal of Forensic and Legal Medicine

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“…Determining the time since deposition of a biological stain at a crime scene can provide crucial information to a forensic investigation, indicating either when a crime was committed, or whether the biological evidence was deposited at the time of a known crime event. Previous studies have indicated that the relative expression ratio (RER) of reference genes (ACTB/18S) can be used to indicate the age of blood [1,2], saliva [3] or hair samples [4]. However, it has also been suggested that there are limitations to this method when applied to samples that are mixtures of more than one type [3].…”

Section: Introductionmentioning

confidence: 99%

Evaluating the effect of body fluid mixture on the relative expression ratio of blood-specific RNA markers

Alshehhi

Haddrill

2020

Forensic Science International

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The estimation of the time elapsed since a biological stain was deposited at a crime scene can provide crucial information to a forensic investigation, indicating either when a crime was committed, or whether the biological evidence was deposited at the time of a known crime event. This would enable the investigators to limit the number of suspects and to assess alibis. The relative expression ratios (RERs) of body fluidspecific RNA markers are promising molecular tools for indicating the age of biological stains. However, the nature of some forensic samples found at crime scenes could be challenging, as they frequently occur in a mixture of different body fluid types. The research presented here has utilised reverse transcription quantitative PCR (RT-qPCR) to explore the impact of bloodstains being present in mixtures with other body fluids (saliva or semen) on the resulting RERs of blood-specific markers. The expression level of three blood-specific markers (HBA, HBB and miR16) along with two reference genes (18S and U6) were analysed across multiple ageing time points in pure and mixed bloodstains. For some markers, no significant differences were found when comparing RERs in pure and mixed bloodstains, however some RERs were altered in mixed stains. This indicates that the presence of body fluid mixtures may have a significant effect on the RERs of some blood-specific markers. This should therefore be considered when selecting markers for estimating the age of stains, particularly when multiple body fluids are thought to be present.

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“…While characterizing the age of biological fluids including semen and bloodstains from crime scenes is a well-accepted approach in forensic sciences [1], aging of hair samples collected at crime scenes has been less studied, with the exception of the use of the time-dependent decay of highly abundant RNAs in hair samples in forensics [2]. As such, there is a critical need to evaluate systematically ex vivo aging of hair by taking advantage of biophysical analyses [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

Shankar

Guimarães

Napoli

et al. 2020

Journal of Forensic Sciences

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Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.

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An RNA Expression Method for Aging Forensic Hair Samples

Cited by 19 publications

References 15 publications

Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

Evaluating the effect of body fluid mixture on the relative expression ratio of blood-specific RNA markers

Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

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