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P081 – From Powder to Problems: The Impact of Illicit Drugs on DNA Extraction Efficiency
Drug synthesis requires a series of steps, many of which involve human interaction. Any human involvement opens the opportunity for the incorporation of DNA from those making, packaging or transporting the illicit material. The lack of hygienic conditions and infrequent wearing of personal protective clothing adds to the chance that human DNA is detectable in both illicit material and drug paraphernalia. The analysis of illicit drugs for the presence of human DNA provides an opportunity to gain information as to ‘who’ is involved in the supply chain of illicit drugs. Given the known inhibitory effects of numerous illicit drugs and related compounds on DNA analysis, such as PCR, it is crucial to understand the effectiveness of currently used DNA extraction kits to successfully remove these compounds while extracting sufficient DNA for downstream DNA profiling. To do this, four common illicit drugs (methamphetamine HCl, heroin HCl, MDMA HCl and GHB Na) in addition to two precursors of methamphetamine (pseudoephedrine HCl and phenyl-2-propanone [P2P]) were spiked with saliva and the DNA extracted. Two DNA extraction kits were selected to evaluate silica columns compared to paramagnetic beads, the QIAGEN QIAamp® DNA Investigator kit and the Promega DNA IQ™ system. DNA quantification of these samples yielded significantly more DNA recovery for each drug, except P2P, when extracted using DNA Investigator compared to DNA IQ. Similarly, peak heights and heterozygous peak height balance were, on average, improved when samples were extracted with DNA Investigator compared to DNA IQ. Regardless of the illicit drug or DNA extraction kit used, no inhibition was detected during DNA quantification or profiling, indicating reduced DNA yields were caused by inefficient DNA extraction rather than inhibition of the PCR processes. All samples extracted using DNA Investigator yielded complete DNA profiles, while DNA IQ yielded near-complete profiles using VeriFiler Plus, ultimately resulting in extremely strong likelihood ratio values for the donor from all samples. The generation of informative DNA profiles, despite the presence of illicit drugs, using two commercially available DNA extraction kits highlights the potential to implement these sample types into operational laboratories with minimal changes to standard DNA analysis workflows.
Authors
- Madison Nolan (Flinders University, Australia)
- Paul Kirkbride (Flinders University, Australia)
- Adrian Linacre (Flinders University, Australia)
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