Trace DNA Sampling Success from Evidence Items Commonly Encountered in Forensic Casework |
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| Authors: | Renata Dziak M.Sc. Amy Peneder H.B.Sc. Alicia Buetter H.B.Sc. Cecilia Hageman Ph.D. LL.B. |
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| Affiliation: | 1. Biology Section, Centre of Forensic Sciences, Ministry of Community Safety and Correctional Services, Toronto, ON, Canada M3M 0B1;2. Biology Section, Centre of Forensic Sciences, Ministry of Community Safety and Correctional Services, Sault Ste. Marie, ON, Canada P6A 6V4;3. Toronto Police Service Forensic Identification Services, North York, ON, Canada M9N 2V3;4. Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada L1H 7K4 |
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| Abstract: | Trace DNA analysis is a significant part of a forensic laboratory's workload. Knowing optimal sampling strategies and item success rates for particular item types can assist in evidence selection and examination processes and shorten turnaround times. In this study, forensic short tandem repeat (STR) casework results were reviewed to determine how often STR profiles suitable for comparison were obtained from “handler” and “wearer” areas of 764 items commonly submitted for examination. One hundred and fifty‐five (155) items obtained from volunteers were also sampled. Items were analyzed for best sampling location and strategy. For casework items, headwear and gloves provided the highest success rates. Experimentally, eyeglasses and earphones, T‐shirts, fabric gloves and watches provided the highest success rates. Eyeglasses and latex gloves provided optimal results if the entire surfaces were swabbed. In general, at least 10%, and up to 88% of all trace DNA analyses resulted in suitable STR profiles for comparison. |
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| Keywords: | forensic science DNA typing trace DNA touch DNA handler DNA sampling efficiency swabbing short tandem repeats |
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