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A comparative study for the isolation of exogenous trace DNA from fingernails

Published:January 04, 2019DOI:https://doi.org/10.1016/j.fsigen.2018.12.009

      Highlights

      • Lysis buffer soak sampling method extracts more female endogenous degraded DNA.
      • Marginally higher likelihood ratios were obtained for the swab samples.
      • The swabbing sampling method appears to be the best sampling method.
      • If the number of contributors was underestimated then false exclusions could occur when performing mixture deconvolution using STRmix™.
      • DNA can remain under fingernails and on the skin even after showering.

      Abstract

      Often fingernails from a victim or suspect involved in a physical assault, such as murder or sexual assault, are submitted to crime laboratories for DNA testing of foreign/exogenous biological material; however, very few studies have been conducted comparing the effectiveness of different sampling methods on the removal of foreign/exogenous DNA while minimizing the fingernail endogenous DNA. In this study three different sampling methods (swabbing, PBS soak, and PrepFiler® lysis buffer soak) were compared in order to identify one that minimizes the amount of endogenous DNA removed and maximizes the amount of foreign/exogenous male DNA removed. The samples were processed using the Tecan HIDEVO150 robot in order to reduce analyst time and the DNA mixtures were interpreted using the probabilistic genotyping software STRmix™. For each sampling method the quantity of male DNA, the mixture proportions, the number of foreign/exogenous male alleles detected, the amount of DNA degradation, and the discrimination power via the likelihood ratio obtained for the foreign/exogenous male DNA donor were determined and compared. The PrepFiler® lysis buffer soak and swabbing sampling methods appear to be equally effective at removing foreign/exogenous DNA from fingernails; however, the lysis buffer soak sampling method extracts more female endogenous DNA from the fingernail and the female DNA is degraded. Marginally higher likelihood ratios were obtained for the swab samples versus the PrepFiler® lysis buffer soak samples; therefore, it was determined that the swabbing sampling method was the best sampling method for the recovery of foreign exogenous DNA from fingernails while minimizing the amount of endogenous DNA removed.

      Keywords

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      References

        • Nurit B.
        • Anat G.
        • Michal S.
        • Lilach F.
        • Maya F.
        Evaluating the prevalence of DNA mixtures found in fingernail samples from victims and suspects in homicide cases.
        Forensic Sci. Int. Genet. 2011; 5: 532-537
        • Matte M.
        • Williams L.
        • Frappier R.
        • Newman J.
        Prevalence and persistence of foreign DNA beneath fingernails.
        Forensic Sci. Int. Genet. 2012; 6: 236-243
        • Dowlman E.A.
        • Martin N.C.
        • Foy M.J.
        • Lochner T.
        • Neocleous T.
        The prevalence of mixed DNA profiles on fingernail swabs.
        Sci. Justice. 2010; 50: 64-71
        • Malsom S.
        • Flanagan N.
        • McAlister C.
        • Dixon L.
        The prevalence of mixed DNA profiles in fingernail samples taken from couples who co-habit using autosomal and Y-STRs.
        Forensic Sci. Int. Genet. 2009; 3: 57-62
        • Cook O.
        • Dixon L.
        The prevalence of mixed DNA profiles in fingernail samples taken from individuals in the general population.
        Forensic Sci. Int. Genet. 2007; 1: 62-68
        • Hebda L.M.
        • Doran A.E.
        • Foran D.R.
        Collecting and analyzing DNA evidence from fingernails: a comparative study.
        J. Forensic Sci. 2014; 59: 1343-1350
        • Cline R.E.
        • Laurent N.M.
        • Foran D.R.
        The fingernails of Mary Sullivan: developing reliable methods for selectively isolating endogenous and exogenous DNA from evidence.
        J. Forensic Sci. 2003; 48: 1-6
        • Bozzo W.R.
        • Colussi A.G.
        • Ortíz M.I.
        • Laborde L.
        • Pilili J.P.
        • Carini G.
        • Logo M.M.
        Analysis of DNA from fingernail samples in criminal cases.
        Forensic Sci. Int. Genet. Suppl. Ser. 2015; 5: e601-e602
        • Bright J.-A.
        • Curran J.M.
        • Buckleton J.S.
        The effect of the uncertainty in the number of contributors to mixed DNA profiles on profile interpretation.
        Forensic Sci. Int. Genet. 2014; 12: 208-214
        • Taylor D.
        • Buckleton J.S.
        • Bright J.-A.
        Does the use of probabilistic genotyping change the way we should view sub-threshold data?.
        Aust. J. Forensic Sci. 2015; 49: 78-92
        • Timken M.
        • Klein S.
        • Buoncristiani M.
        Stochastic sampling effects in STR typing: implications for analysis and interpretation.
        Forensic Sci. Int. Genet. 2014; 11: 195-204
        • Bright J.-A.
        • Taylor D.
        • Curran J.M.
        • Buckleton J.S.
        Degradation of forensic DNA profiles.
        Aust. J. Forensic Sci. 2013; : 1-5
        • Moretti T.R.
        • Just R.S.
        • Kehl S.C.
        • Willis L.E.
        • Buckleton J.S.
        • Bright J.-A.
        • Taylor D.A.
        • Onorato A.J.
        Internal validation of STRmix™ for the interpretation of single source and mixed DNA profiles.
        Forensic Sci. Int. Genet. 2017; 29: 126-144
        • Bright J.-A.
        • Richards R.
        • Kruijver M.
        • Kelly H.
        • McGovern C.
        • Magee A.
        • McWhorter A.
        • Ciecko A.
        • Peck B.
        • Baumgartner C.
        • Buettner C.
        • McWilliams S.
        • McKenna C.
        • Gallacher C.
        • Mallinder B.
        • Wright D.
        • Johnson D.
        • Catella D.
        • Lien E.
        • O’Connor C.
        • Duncan G.
        • Bundy J.
        • Echard J.
        • Lowe J.
        • Stewart J.
        • Corrado K.
        • Gentile S.
        • Kaplan M.
        • Hassler M.
        • McDonald N.
        • Hulme P.
        • Oefelein R.
        • Montpetit S.
        • Strong M.
        • Noël S.
        • Malson S.
        • Myers S.
        • Welti S.
        • Moretti T.
        • McMahon T.
        • Grill T.
        • Kalafut T.
        • Greer-Ritzheimer M.M.
        • Beamer V.
        • Taylor D.A.
        • Buckleton J.S.
        Internal validation of STRmix™ — a multi laboratory response to PCAST.
        Forensic Sci. Int. Genet. 2018; 34: 11-24
      1. Applied Biosystems Quantifiler™ HP and Trio Quantificaiton kits User Guide, Publication Number 4485354, Revision G (April 2017).

      2. Applied Biosystems GlobalFiler™ PCR Amplification Kit User Guide, Publication Number 4477604, Revision E (July 2016).

      3. Applied Biosystems 3500/3500xL Genetic Analyzer User Guide, Publication Number 4401661, Revision C (June 2010).

      4. Applied Biosystems GeneMapper® ID-X Software Version 1.4, Publication Number 4477684, Revision B (December 2012).

      5. Institute of Environmental Science and Research (December 2014) STRmix User’s manual, version 2.0, www.strmix.com.

      6. Prepfiler™ Forensic DNA Extraction Kit User Guide, Part Number 439093, Revision B (November 2008).