Improving Evidentiary and Reference Samples Recovery and ...

Improving Evidentiary and Reference Samples Recovery and Stabilization at the Point of Collection for Enhanced ID Profiling Dr. Bassam El-Fahmawi & Dr. Geoffrey Routh

Fiction vs. Reality

Vs.

Trace DNA - Touch DNA (LCN) – Contact DNA – Evidentiary Samples – Crime Scene DNA

Majority of Evidentiary Samples are Collected by Swabs

Factors affecting DNA Integrity & Recovery  Irreversible binding to swab material  Nucleases  Microbial contamination  Temperature fluctuations  Heat  Humidity  UV light  Improper collection  Storage conditions  Transport conditions & transit time Backlog Are Not Static (>30 day)

The Backlog Dilemma: A Global Problem

Processing Evidentiary Material from a Crime Scene Step #

Description

1 2 3

Screen Identify Collect

4

Dry

5 6 7 8

package Reporting and documentation Transport Store

9

Cut swab/ punch FTA card

10 11 12

lyse Extract Quantify

13

STR profiling

14 15

Data Analysis Report

Time Spent (mins)

30 min/Sample

10 min /Sample 20-60% Further Anlysis (?? Mins)

C

Drying Effect on DNA Quality & Recovery

• DNA recovery yields post drying = 20 -30% • DNA Integrity • Processing Efficiency

Recover Evidentiary Sample & Stabilize at the Point of Collection from Swabs No Swab Transported, Liquid Stabilization

1- Recover collected Evidentiary Material 2- Stabilize and Lyse Collected Material

Testing for DNA Quality, Recovery Efficiency & Stability Efficient Recovery

Concentrate

Any Swab Material

Long Term Room Temperature Stable & No PCR Inhibition

Collecting and Stabilizing Evidentiary Samples: The Experiment Objective • To assess the efficiency of the iSWAB-ID sample collection device in the collection and stabilization of both reference and evidentiary samples by assessing the usability of purified DNA in human ID profiling assays. Experimental Design Collect Reference and mocked evidentiary Samples into the collection Device (400 µL) Transport to processing lab by standard mail Store Samples at room temperature Extract 100 µL from each sample at Day 2 and day 14 Quantify DNA and ID profiling Archive remaining volume at room temperature for future use

Collecting and Stabilizing Evidentiary Samples: The Process

1 Fresh Drop of blood on laminate floor 2 Coffee Cup Rim 3 One day old blood spot on carpet 4 Onne day old dry venous blood spot on laminate floor 5 Lip stick on water bottle rim 6 Two week Old Blood Spot 7 Steering wheel 8 Rim of open soda can 9 Water bottle rim 10 Reference Samples 11 Rape Samle

Swab dry times might vary depending on local temperatures and humidity levels

Collecting and Stabilizing Evidentiary Samples: The Data

DNA concentration from swabs post ISWAB-ID collection: ND Fig 1. A selection of real-world, reference, and simulated evidence samples were collected in iSWAB-ID devices and stored at room temperature. DNA was extracted from 100 µL aliquots, using the AnaPrep Blood DNA extraction kit on AnaPrep 12 instrument, either two days or two weeks after collection. In all cases, PCR-amplifiable Human DNA was recovered from stabilized samples after storage for two weeks at room temperature. All samples were quantified by QIAGEN Investigator Quantiplex Kit targeting Human DNA. A) Low copy samples, B) Medium copy samples, C) High copy samples, D) Amplification blot for all samples including standard curve, VIC, (two days & 2 weeks samples), ND: Not Detected

STR Profiling with Promega PowerPlex 16 HS 2 Days

Lipstick on a Cup Rim

14 Days

Simulated Rape

Based on Sorensons Foresnics First Pass STR Profiling Analysis: Samples are Suitable for Comparison Purposes

Compatibility with Direct PCR- ID Profiling: No DNA Extraction Required

ABI Identiflier Direct PCR STR kit

Processing Evidentiary Material from a Crime Scene: A Revised Look with iSWAB-ID

Significant Improvement on Processing Efficiency: Faster Collection  Higher First Pass Rate Higher Sample processing Throughput

Summary and Conclusions  The iSWAB-ID sample collection device efficiently recovered and stabilized DNA of forensic significance at the point of collection.  The iSWAB-ID sample collection device stabilized DNA remained of sufficient quality to analyze for at least 2 weeks at ambient temperature.  Unlike processing swabs, collected samples allows for multiple runs for analysis and archiving purposes for future analysis. Long shelf life allows for ample time for sample storage and processing Proper recovery and stabilization of DNA samples of forensics significance at the point of collection is critical for improving the STR profiling call rates,and especially important for maintaining the integrity of the collected sample during protracted transit or processing backlogs

Acknowledgments

Dr. Hyacinth Ntchobo

Dr. Geoff Routh Dr. Zhongdong Liu Dr. Bingfang Huan

Thank You!

Dr. Lars Moritson Patricia Ethington Krista Lundgren

Dr. Ahmad Refaat