The prevalence of mixed DNA profiles on fingernail swabs

Received 29 January 2009; received in revised form 25 March 2009; accepted 28 March 2009. published online 12 May 2009.

Abstract

There is a general acceptance that cellular material will transfer from one person to another person's fingernails through everyday contact. However, the level or degree of contact required to transfer sufficient cellular material in order to obtain a DNA profile is not known. This study examined swabs from the fingernails of 40 volunteers and compared the DNA profiles obtained to the daily activities of that individual. The majority (78%) of high level profiles obtained were associated with recent intimate contact. However, high level profiles were also obtained from the fingernails of individuals who shared accommodation with their partner, flatmates and/or children. Low level profiles and single profiles were associated with all levels of contact.

Keywords: Fingernail, Swabs, DNA profiling, Mixtures

a Centre for Forensic Science, University of Strathclyde, Glasgow, G1 1XW, UK

b SPSA, Forensic Services (Edinburgh), Forensic Science Laboratory, 11 Howden Hall Road, Edinburgh, EH16 6TL, UK

c Department of Statistics, 15 University Gardens, University of Glasgow, G12 8QQ, UK

Corresponding author. Tel.: +44 131 666 1212.

PII: S1355-0306(09)00059-8

doi:10.1016/j.scijus.2009.03.005

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