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The potential impact of secondary transfer and persistence of deoxyribonucleic acid (DNA) on forensic casework
Forensic Science International: Genetics Supplement Series 3 (2011) e542
Contents lists available at ScienceDirect
Forensic Science International: Genetics Supplement Series journal homepage: www.elsevier.com/locate/FSIGSS
The potential impact of secondary transfer and persistence of deoxyribonucleic acid (DNA) on forensic casework L.M. Walton *, A.R. Jackson, H.A. Mountain Staffordshire University, Stoke-on-Trent, England,
A R T I C L E I N F O
Article history: Received 12 September 2011 Accepted 27 September 2011 Keywords: Secondary transfer DNA persistence Forensic DNA analysis Trace DNA
Due to increases in the sensitivity of DNA analysis it is now possible to recover DNA profiles from handled objects. However, alongside the improvements in the level of detection comes the potential increase in contamination, from known and unknown sources. The aim of this research was to undertake a series of experiments, designed to examine the potential for secondary transfer of DNA. DNA was extracted using the Qiagen Microkit
* Corresponding author. Tel.: +44 01 782 295746. E-mail address: [email protected] (L.M. Walton). 1875-1768/$ – see front matter ß 2011 Published by Elsevier Ireland Ltd. doi:10.1016/j.fsigss.2011.09.118
followed by amplification with the AmpFlSTR1 IdentifilerTM or SGM PlusTM systems. These studies have indicated that secondary transfer does exist both when the vehicle for transfer is an object or another person’s hand. Perhaps more importantly, the results indicated that when an object was handled by two different individuals, and partial profiles were retrieved, the dominant profile was not necessarily that of the final handler. This may suggest that the predominance of a subjects’ profile from a handled object is dependent on how well the individual sheds their DNA, and not solely on the order in which the subjects handled the object. This could have a major impact on the information gained from seized objects at crime scenes, as it disputes the theory that the final person to handle an object would be the major contributor to a mixed DNA profile. This presentation will discuss the results of these experiments, further research into DNA transfer and persistence variables, as well as broadly examining the potential impact the findings may have on Forensic Casework.
Contents lists available at ScienceDirect
Forensic Science International: Genetics Supplement Series journal homepage: www.elsevier.com/locate/FSIGSS
The potential impact of secondary transfer and persistence of deoxyribonucleic acid (DNA) on forensic casework L.M. Walton *, A.R. Jackson, H.A. Mountain Staffordshire University, Stoke-on-Trent, England,
A R T I C L E I N F O
Article history: Received 12 September 2011 Accepted 27 September 2011 Keywords: Secondary transfer DNA persistence Forensic DNA analysis Trace DNA
Due to increases in the sensitivity of DNA analysis it is now possible to recover DNA profiles from handled objects. However, alongside the improvements in the level of detection comes the potential increase in contamination, from known and unknown sources. The aim of this research was to undertake a series of experiments, designed to examine the potential for secondary transfer of DNA. DNA was extracted using the Qiagen Microkit
* Corresponding author. Tel.: +44 01 782 295746. E-mail address: [email protected] (L.M. Walton). 1875-1768/$ – see front matter ß 2011 Published by Elsevier Ireland Ltd. doi:10.1016/j.fsigss.2011.09.118
followed by amplification with the AmpFlSTR1 IdentifilerTM or SGM PlusTM systems. These studies have indicated that secondary transfer does exist both when the vehicle for transfer is an object or another person’s hand. Perhaps more importantly, the results indicated that when an object was handled by two different individuals, and partial profiles were retrieved, the dominant profile was not necessarily that of the final handler. This may suggest that the predominance of a subjects’ profile from a handled object is dependent on how well the individual sheds their DNA, and not solely on the order in which the subjects handled the object. This could have a major impact on the information gained from seized objects at crime scenes, as it disputes the theory that the final person to handle an object would be the major contributor to a mixed DNA profile. This presentation will discuss the results of these experiments, further research into DNA transfer and persistence variables, as well as broadly examining the potential impact the findings may have on Forensic Casework.