DNA-free does not mean RNA-free-The unwanted persistence of RNA.

Schyma, Christian; Madea, Burkhard; Müller, Rolf; Zieger, Martin; Utz, Silvia; Grabmüller, Melanie (2021). DNA-free does not mean RNA-free-The unwanted persistence of RNA. Forensic science international, 318, p. 110632. Elsevier 10.1016/j.forsciint.2020.110632

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Contact shots to the head often provoke a transfer of biological traces into firearm barrels, which are not visible at endoscopic inspection. STR-PCR can amplify these latent traces and assign them to the victim. Via RNA-DNA-co-extraction also miRNA can be detected, which allow a conclusion to be drawn about the body fluid or tissue. Molecular genetic analysis of experimental stains in firearm barrels requires the guarantee that the barrel is initially free of any nucleic acid. Twelve shots were fired to so-called "reference cubes" (10 % gelatine, 12 cm edge length, embedded paint-blood-pad) using three current handguns: from 20 and 30 cm distance, four at close range (1-2.5 cm) and six contact shots. After endoscopic examination and swabbing of the barrels, a previously described mechanical and chemical cleaning using DNAExitusPlus™ was performed. The inner surface of the barrel was thoroughly wiped off using moistened forensic swabs, which were submitted to RNA-DNA-co-extraction. The combined thorough mechanical cleaning with Ballistol® and the application of DNAExitusPlus™ eliminated any profilable DNA in all samples. However, in 10 of 12 samples RNA concentrations between 0.11 - 0.79 ng/μl were measured. Furthermore, in 9 of 12 samples blood-specific miRNA (miR-451a) was detected. Summarizing, none of the experimentally contaminated barrels was RNA-free despite the performed cleaning procedure. Further investigation showed, that even "professional" cleaning by a gunsmith did not remove RNA.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Service Sector > Institute of Legal Medicine > Forensic Molecular Biology
04 Faculty of Medicine > Service Sector > Institute of Legal Medicine
04 Faculty of Medicine > Service Sector > Institute of Legal Medicine > Forensic Medicine

UniBE Contributor:

Schyma, Christian; Zieger, Martin and Utz, Silvia

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1872-6283

Publisher:

Elsevier

Language:

English

Submitter:

Antoinette Angehrn

Date Deposited:

20 Jan 2021 17:14

Last Modified:

21 Jan 2021 01:35

Publisher DOI:

10.1016/j.forsciint.2020.110632

PubMed ID:

33302243

Uncontrolled Keywords:

Backspatter Biological traces Firearms Micro RNA Molecular genetics

BORIS DOI:

10.48350/150501

URI:

https://boris.unibe.ch/id/eprint/150501

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