Evaluation of collection and extraction methodologies of latent fingerprints for military application

Abstract

A B S T R A C TLatent fingerprint has been commonly used by Brazilian Army forensic experts as an effective tool for personal identification in crime scene investigations. In cases whereas samples are considered unusable for dactyloscopy, genetic analysis appears as a complementary method that prevents waste of expert testimony. The aim of our study was to standardize DNA collection and extraction techniques in two types of surfaces: glass and metal, in order to adapt these methodologies to military reality. Fingerprints were collected using two swabbing solutions: NaCl 0.9% and sodium dodecyl sulfate 2%. DNA was isolated by testing two methods: Lysis solution: SDS/proteinase and QIAmp 1 DNA Investigator 1 Kit (Qiagen). PCR amplification was performed with AmpFLSTR 1 MiniFiler TM Kit (Life Technologies). It was observed that Lysis extraction with NaCl 0.9% swabbing solution gave satisfactory results for samples collected both on glass and metallic supports.

Análise de Impressão Digital no Brasil: Uma Revisão Bibliométrica 2010-2019

“…Protocols for the use of traditional developers for the development of fingerprints on exploded or unexflated gun cartridges have been proposed and tested [14][15][16] . Another topic widely covered refers to studies about the collection of genetic material from digital printing [17][18][19] . Finally, the importance of fingerprint analysis for the identification of false documents was also studied 20 .…”

“…Oliveira et al 17 studied several methodologies and proposed a standardization of techniques for collecting and extracting DNA from fingerprints deposited on glass and metal surfaces (classified as non-porous substrates) to adapt these methods for military application. Three volunteers deposited their fingerprints by pressing the surface of 24 slides for 30 seconds.…”

Collecting touch DNA from glass surfaces using different sampling solutions and volumes: Immediate and storage effects on genetic STR analysis

“…However, due to its high variability, touch DNA cannot be accurately measured and applied in a defined manner in a realistic scenario. As many other studies done beforehand [5,7,15,30,34,44], we carefully prepared each plate with one donor's DNA with the individual's similar pressure and conditions, to get consistent and realistic amounts on the plates for all solutions and volumes tested. Sampling fields were randomly assigned to different conditions.…”

“…However, an overall higher DNA yield was expected due to the "good" shedder status of the donor and the study objects being touched not only once, but eight times per cycle. One explanation could be the large surface area being touched and retouched and not constantly in contact with the donor's hand as described for most studies applying small glass substrates (i.e., microscopy slides, vials [7,34,44]). Especially for SDS, these results are congruent with the study by Thomasma et al [5], who also predicted no negative impacts of SDS swabbing in immediately processed samples as well as after prolonged storage, which was not further specified.…”

“…In contrast to the well-investigated potential of the diverse tools, methods, and practices, little is known about the proper medium for cell recovery and DNA uptake, which is particularly true for the most commonly used solution, that is, nuclease-free water, which is also currently used in our laboratory. However, a wide range of other swabbing solutions, such as sodium dodecyl sulfate (SDS) [27,28], Triton X-100 [29,30], isopropanol [31][32][33], ethanol [33], isotonic sodium chloride (NaCl) [34], phosphate-buffered saline (PBS) [20,21,35,36], and Tween-20 [5,20,21] have not only been introduced as suitable in cell culture but have also been proposed as effective in forensic investigations. However, so far, comprehensive comparison studies of commercially available solutions and potential storage effects are rare [5,21,32], especially for DNA recovery from touch samples.…”