Young Investigator Jan Fleckhaus discusses his research on age estimation
November 11, 2019
Our Young Investigator series allows us to acknowledge rising scientists in the forensic field. We hope that they inspire you with their story, as they are our future!
Continuing our blog series, next we have Jan Fleckhaus, Ph.D. student at the Institute of Legal Medicine, Cologne, Germany. His research focuses on DNA methylation-based age prediction and optimization of the Pyrosequencing technology for its application in routine forensic work.
Tell us about your background and how you became interested in forensic science?
As a son of two biologists, my interest in biology was set in the early years and grew along with my education. Consequently, I decided to study biology after finishing my A-Levels. At that time and during my bachelor’s degree, I didn’t recognize forensic science at all since there were no relevant courses in the curriculum. However, during my studies, I developed a strong interest in human genetics. Then, during my masters the curriculum foresaw a self-organized internship at a department of one’s own choice. When researching different departments related to human genetics, I recognized forensic molecular biology for the first time and decided to apply for an internship at the Institute of Legal Medicine in Cologne. That was in late 2015. I got the position of an intern and decided to stay at the institute since it continued to spark my interest in forensic molecular biology. After receiving my master’s degree in late 2016, I was offered the position of a Scientific Assistant which I accepted to keep up with my doctoral thesis.
Can you provide a summary of the project you are working on?
The identification of persons or matching biological stains, for example from a crime scene, to a person via DNA genotyping is the most powerful tool of forensic molecular biology.
Nevertheless, the method has a strong limitation which is the requirement of a reference profile, without which the identification of a person is impossible. Since reference profiles are in some cases not available, current research in forensic molecular biology aims to develop new methods to retrieve information about phenotypic characteristics directly from the DNA, referred to as
Forensic DNA Phenotyping (FDP). The generated ‘biological witness’ ought to support police investigations to find those persons that match to the evidence sample. In the course of FDP, the prediction of the chronological age is a promising approach. In recent years, different studies identified strong associations between the methylation at some CpG (Cytosine followed by a Guanine) sites and the chronological age, indicating that the methylation pattern at these sites can serve as a sufficient molecular biomarker for age determination. The goal of current research and the topic of my doctoral project is the validation of those biomarkers for routine forensic application. Thereby, I’m investigating the performance of the different age-dependent CpG sites (age CpGs) in individuals with different genetic and environmental background. These investigations are highly important because DNA methylation as an epigenetic modification can be affected by both genetic constitution and environment. Since DNA-based age prediction is a comparative method between the evidence sample and a number of reference samples, it is required that all samples share the same age-dependent methylation change at certain age CpGs. Consequently, any factor that exclusively occurs and affects the methylation of the age CpGs in a certain group of individuals, leads to a biased age prediction.
What do you find most interesting about your project? Have you seen any surprising results?
Honestly, it is difficult to name a particular thing that I like most about my project, since there are several aspects of it that I find really interesting. One aspect is the very smart idea of using a molecular marker such as DNA methylation as a readout of the chronological aging process. It is fascinating to me that there seems to be a predetermined program inside the cells that is executed in such a timely fashion among all humans. Another aspect I really like is the impact of my work
– working on technologies that will help clarify real legal cases is highly motivating.
What are the benefits of your research?
A validated tool for age prediction from biological stains has major benefits in different legal scenarios. As mentioned earlier, one is the application to biological stains a perpetrator left at a crime scene. The information about the chronological age of an unknown perpetrator can narrow down the number of suspects and prove very useful in police investigations. Another scenario is the application of the method to unknown dead bodies or parts of it, where the information about the chronological age can help identify the person.
What are the major challenges you face with regards to the application of this new technology and how do you overcome them?
My project is all about solving the major challenges of DNA methylation-based age prediction, which is the result of genetic and environmental factors that can potentially bias the age prediction outcome. At the technology level, I don’t expect any major challenges because the experimental workflow appears to be highly robust.
Which QIAGEN products do you use and what do you like about the products?
I’m exclusively using QIAGEN instruments and reagents for my experiments. I perform DNA extractions using either the EZ1 or the QIAsymphony instrument. For bisulfite conversions, I’m using the EpiTect Fast Bisulfite Conversion Kit, and for the subsequent PCR reactions, I use the PyroMark PCR Kit. The quantitative methylation analysis is conducted on the PyroMark Q48 instrument using the PyroMark Q48 Advanced Reagents.
What I like most is the easy handling of the products and the fast processing of the reactions. I am able to perform the entire workflow from DNA extraction to sequencing in a single day. This is a great advantage of the workflow especially for further application in routine casework.
Outside of forensic science, what are your hobbies?
Outside of forensic science I have several hobbies like cooking, traveling, playing the guitar and doing different kinds of sports. However, I’m spending most of my time on the training ground for field hockey as my team prepares for the first German League. On the weekends, we are playing somewhere in Germany for national competitions, but also go abroad for international competitions.
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