Presentation number: FG 7
EFFECT OF OVER-THE-COUNTER DRUGS ON DNA ANALYSIS OF BLOOD INGESTED BY MEDICINAL LEECHES
Dipesh Patel1, Dan Sykes2, Reena Roy3
1Undergraduate Student, Schreyers Honors College, The Pennsylvania State University, University Park, PA, USA, 2Chemistry Department, The Pennsylvania State University, University Park, PA, USA, 3The Pennsylvania State University, Forensic Science Program, Department of Biochemistry and Molecular Biology, University Park, PA, USA
Painkillers, such as aspirin (acetylsalicylic acid), are used by many to alleviate the pain associated with common ailments. Although the half-life for aspirin is only 2-5 hours, it is possible that there may still be residual drug in the body post-mortem. Hence, if a medicinal leech, Macrobdella Decora, feeds on the blood of a victim or a suspect who had recently ingested an analgesic, it may be possible to simultaneously obtain a complete DNA profile and drug identification from the blood extracted from the crop (midgut) area of the leech. The potential for generating a DNA profile depends on whether or not acetylsalicylic acid inhibits amplification due to the acid having a phenol group. Human blood was spiked with 25 ppm and 50 ppm aspirin solutions followed by DNA extraction at 0, 24 and 48 hours. The extracted DNA was quantified and amplified using the PowerPlex® Fusion 6 C for autosomal STR and PowerPlex® Y-23 system for Y-STR analysis. HPLC was used to determine the presence of aspirin. These amplified products were analyzed by capillary electrophoresis and fragment analysis of these reference samples were completed using appropriate software. Blood mixed with the aspirin was fed to the leeches which were then euthanatized by freezing at 0, 12, and 24 hours after being fed. Human blood from their crop was extracted and analyzed for the presence of aspirin and for generating the DNA profiles. Since complete autosomal and Y-STR profiles were obtained from blood spiked with aspirin and ingested by the leeches, it is concluded that inhibition was not caused by acetylsalicylic acid. No inhibition was noted in the quantification data and DNA amplification resulted in complete profiles from the reference blood samples mixed with aspirin and from the blood stored in the midgut of the medicinal leeches. All profiles were consistent within and between samples, thus indicating that medicinal leeches can be a valuable source of forensic evidence.
Key words: Medicinal leeches, Aspirin, Autosomal STR, Y-STR