Young Investigator Lisa Dierig discusses her research on forensic ‘touch DNA’ evidence

Tell us about your background and how you became interested in forensic science?

I always wanted to work in law enforcement. Unfortunately, I did not meet the requirements to join the German police force. In the Netherlands I came across a university offering a Major in Forensic Sciences. This subject provides broad education across a variety of forensic disciplines. During the internships I then discovered my passion for forensic DNA analysis. After having worked at different institutions, trying to identify individual cannabis plants and assigning rattle snakes to their geographic origin, I will now specialize in the analysis of micro traces for human identification.

Micro traces such as shed hair or skin cells are commonly found in forensic casework. Shed skin mostly originates from the contact between two individuals or an individual and an object, and such traces are therefore called touch DNA. Since most touch DNA samples only contain minute amounts of DNA, firstly I optimize the process of collecting all of the DNA present. However, doing so will necessarily gather DNA from all contributors and create admixed profiles. So secondly, I try to identify ways to minimize the generation of mixtures in touch DNA samples by further specifying the collection method, optimizing the analysis and looking into alternative strategies other than STR typing.

Please describe your typical day in the lab.

First thing in the morning I plan and schedule my day around the many things going on in a forensic lab. Sometimes I help with routine casework trying to solve thrilling cases or testing new kits and methods for implementation into our workflow, and always eager to find the tiniest traces. Other days I can focus on my research project, preparing, performing and evaluating experiments, troubleshooting issues and discussing with fellow researchers. I also passionately supervise interns who are either having their first experience in a lab outside school or university or going through their first own research project.

What do you find most interesting about your project? Have you seen any surprising results?

I love the diversity of methods and approaches in my project. I got so many strategies to choose from and to compare. Every single one has an individual facet contributing to the success of another part of the analysis. Identifying the benefits or minimizing disadvantages to optimize the workflow is what the project thrives on. I have not had the ‘big’ surprising result yet, but many small surprises come around the corner especially when I least expect them.

What are the benefits of your research?

Ideally, in the end there is a method that can be incorporated into routine case work to identify and estimate the presence of touch DNA. After collecting the maximum of available DNA and preventing co-sampling of DNA from multiple donors at the same time, the optimized STR analysis method allows generation of DNA profiles from minute amounts of DNA. I personally benefit from the opportunity to get in touch and discuss with other researchers and learn about their approaches. In my opinion, exchange between working groups is a great way to collect and share ideas on research projects.

What are the major challenges you face with regards to sample collection, STR processing and data analysis?

Minute amounts of DNA represent a major challenge in my research. Contamination can occur easily, so all consumables and reagents I use must be absolutely free of foreign DNA. I usually work with small reagent volumes, and therefore need them to perform optimally. High sensitivity is particularly required to obtain results from these difficult samples.

Which QIAGEN products do you use and what do you like about the products?

I routinely use the Investigator Quantiplex Pro Kit and the Investigator ESSplex SE QS Kit and like the ease of handling as well as the sensitivity and robustness of the kits. The Quantiplex Pro data handling tool is very intuitive and the Excel format allows me to use it even on my private computer to prepare runs or analyze data. I am looking forward to trying other QIAGEN kits such as the GO! Kits, e.g. for direct PCR applications.

Outside of forensic science, what are your hobbies?

I am into outdoor activities such as skiing, running and hiking, and love spending time in the mountains, but am also a passionate musician (play the clarinet).

You can learn more about Lisa’s work from her conference presentation slides presented at the 7th QIAGEN Investigator Forum.

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