The Tightness of the Cotton Swabs Meshing Influences the Chances of Getting Conclusive DNA Profiles
- *Corresponding Author:
- Sarah L Leake
School of Criminal Justice
Institut de police Scientifique
University of Lausanne, Batochime
1015 Lausanne Dorigny, Switzerland
E-mail: [email protected]
Received date: April 10, 2014; Accepted date: June 02, 2014; Published date: June 09, 2014
Citation: Rocque MJ, Leake SL, Milon MP, Castella V (2014) The Tightness of the Cotton Swabs Meshing Influences the Chances of Getting Conclusive DNA Profiles. J Forensic Res 5:234 doi: 10.4172/2157-7145.1000234
Copyright: © 2014 Rocque MJ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objective: The chance of obtaining a conclusive DNA profile strongly depends on the quantity of biological material that can be recovered from a crime scene sample. Optimizing the collection strategy is therefore of prime interest. A difference in the level of tightness of the cotton meshed around the shaft has been observed between manufacturers and is hypothesized to affect the collection and subsequent release capacity of cotton swabs. Consequently, we compared the performance of cotton swabs from two different suppliers: Applimed SA and DryswabTM.
Methods: These swabs were used to recover 50 ml of blood, either pure or diluted (1:1000 and 1:5000), deposited on both smooth and absorbent surfaces. Performance was compared in terms of ease of use, concentration of extracted DNA, and quality of DNA profiles. DNA quantification was obtained by real-time PCR using the QuantifilerTM Human DNA Quantification Kit. Evaluation of DNA profiles was based on profiles obtained using AmpFlSTR® NGM SElectTM PCR Amplification kit.
Results: When considering smooth surfaces, recovered DNA was more concentrated when using the DryswabTM than the Applimed SA cotton swab. More precisely, DNA concentrations ranged from 15.7 to 28.8 ng/ml and 6.7 to 21.2 ng/ml, respectively for samples of pure blood. The same trend was observed for the absorbent surface, with 2.0 to 5.0 ng/ml and 0.9 to 1.4 ng/ml, respectively.
Conclusion: Our results illustrate that different cotton swabs produce different results in terms of ease of use and quantity of recovered DNA and this should be taken into consideration when choosing which swab to use at both the crime scene and laboratory. More specifically, results from the present study suggest that looser meshing of the cotton fibres forming the swab is preferred.