Sheth, Nidhi and Duffy, Ken R. and Grgicak, Catherine M. (2021) High‐quality data from a forensically relevant single‐cell pipeline enabled by low PBS and proteinase K concentrations. Journal of Forensic Sciences. pp. 1-10. ISSN 0022-1198

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Abstract

Interpreting forensic DNA signal is arduous since the total intensity is a cacophony of signal from noise, artifact, and allele from an unknown number of contributors (NOC). An alternate to traditional bulk- processing pipelines is a single-cell one, where the sample is collected, and each cell is sequestered resulting in n single-source, single-cell EPGs (scEPG) that must be interpreted using applicable strategies. As with all forensic DNA interpretation strategies, high quality electropherograms are required; thus, to enhance the credibility of single-cell forensics, it is necessary to produce an efficient direct-to- PCR treatment that is compatible with prevailing downstream labo-ratory processes.We incorporated the semi-automated micro-fluidic DEPArray™ technology into the single-cell laboratory and optimized its implementation by testing the effects of four laboratory treatments on single-cell profiles. We focused on testing effects of phosphate buffer saline (PBS) since it is an important reagent that mitigates cell rup-ture but is also a PCR inhibitor. Specifically, we explored the effect of decreasing PBS concentrations on five electropherogram-quality metrics from 241 leukocytes: profile drop- out, allele drop-out, allele peak heights, peak height ratios, and scEPG sloping. In an effort to improve reagent use, we also assessed two concentrations of proteinase K. The results indicate that decreasing PBS concentrations to 0.5X or 0.25X improves scEPG quality, while modest modifications to proteinase K concentrations did not significantly impact it. We, therefore, conclude that a lower than recommended pro-teinase K concentration coupled with a lower than recommended PBS concentration results in enhanced scEPGs within the semi-automated single-cell pipeline.

Item Type:	Article
Keywords:	PCR extraction; forensic DNA; PBS; PCR efficienc; phosphate buffer saline; scEP; single-cell electropherogram; single-cell forensic analysis;
Academic Unit:	Faculty of Science and Engineering > Research Institutes > Hamilton Institute
Item ID:	15199
Identification Number:	https://doi.org/10.1111/1556-4029.14956
Depositing User:	Dr Ken Duffy
Date Deposited:	07 Jan 2022 12:56
Journal or Publication Title:	Journal of Forensic Sciences
Publisher:	Wiley
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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