Forensic laboratories extensively employ automated platforms to increase sample throughput, reduce handling errors, and ensure consistency. However, automated processes may result in increased DNA loss compared to manual methods. Kayli will be presenting her research on using the HID Nimbus Presto to tackle challenging samples during her poster presentation at ISHI 34 this September. We chatted with her to learn a little more, and if you’ll be at the conference, be sure to stop by poster #45 to learn more!
Briefly describe your work/area of interest.
In a forensic laboratory, automated extraction is essential for increasing sample throughput while also minimizing errors and maintaining consistency. The high DNA loss that is known to occur during the collection and extraction process is a major concern, especially because automation is known to result in more DNA loss than manual extraction. As a result, the efficacy of a new automated purification platform, the HID NIMBUS Presto System, versus manual extraction for challenging forensic sample types is warranted. The HID NIMBUS Presto System combines Thermo Fisher’s KingFisher™ Presto Purification system and the Hamilton NIMBUS automated liquid handling workstation while using PrepFiler™ and PrepFiler™ BTA extraction scripts. We tested “touch” samples, fired cartridge casings, hair, nails, and teeth from decomposing cadavers, and skeletal samples.
Evaluating extraction efficiencies of a variety of forensic samples is imperative to increase the throughput, but it is important not to sacrifice DNA recovery. This project stemmed from Thermo Fisher Scientific reaching out to my advisor, Dr. Sheree Hughes, at Sam Houston for a collaboration to test whether challenging forensic samples could be extracted on this platform in a manner comparable to manual extraction. Because we were testing so many different sample types, I worked with fellow PhD students Jennifer Snedeker and Natalia Czado to complete this project. At Sam Houston State University, we have access to the Southeast Texas Applied Forensic Science Facility (STAFS), which is a willed body donor facility, so we are afforded the opportunity to conduct research on a wide variety of sample types. We were able to conduct our study on bones subjected to various insults, including burned, buried, and surface decomposition, nails, hair, and teeth from decomposing cadavers, fired cartridge casings, and “touch” samples.
No significant difference in DNA recovery between automation and manual extraction was observed for fired cartridge casings, teeth, surface decomposed, and burned bones (p > 0.05). However, the HID NIMBUS Presto System yielded statistically significantly higher DNA recovery for “touch,” hair, nails, and buried bone samples (p < 0.05). In terms of autosomal allele recovery, there was no significant difference for “touch,” teeth, surface decomposed samples, and fired cartridge casings (p > 0.05). Overall, the HID NIMBUS Presto System demonstrated significantly higher autosomal allele recovery for nail and hair samples (p < 0.05). However, manual extraction outperformed the HID NIMBUS Presto System regarding DNA recovery for buried and burned samples (p < 0.05).
How did you get interested in this work? Why did this particular project appeal?
Originally, I was only going to be responsible for the “touch” sample portion of this project, but as logistics changed, it was decided that it would go under my dissertation. I was excited to be a part of this project due to the exposure to new instrumentation and the opportunity to learn about different sample types that I have never worked on before. I learned the rigorous process of bone sample preparation, which has allowed me to expand my area of research for future projects.
Can you summarize the impact of your work for the audience (ISHI attendees and some general forensic enthusiasts)? How might this advance the field?
The HID NIMBUS Presto System is an additional instrumentation that is available to practitioners that can provide faster turnaround time while delivering DNA recovery and allele recovery similar to manual extraction for the majority of challenging samples.
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