Research Impact is a series that pulls back the curtain of IU Research, showcasing the faculty creating, innovating and advancing knowledge that improves communities and changes lives.
Susan Walsh is a forensic geneticist and associate professor of biology and forensic and investigative sciences at IU Indianapolis Photo courtesy of IU Visuals
The goal of the Walsh lab, nestled on the third floor of the School of Science, is to enhance the understanding of the genetic basis of human physical appearance and ancestry through forensic DNA. By doing so, Walsh can build tools for forensic scientists and improve physical appearance prediction, which can help archaeologists, anthropologists and law enforcement gain a better understanding of what someone may look like based on the DNA they left behind.
Question: What is the focus of your research?
Answer: Our major project is focused on craniofacial morphology or understanding the genetics behind the human face. But we're also working on understanding the genetics behind varying forms of pigmentation across the world, such as eye, hair and skin color.
My work covers several fields. It covers genetics, which is how individuals form and develop; what genes are regulating and controlling the expression of our phenotypes; what we look like; and how our cells are functioning. Then I take that data and use it for something that's more practical, which is the forensic side of my work. But I also look at biology, anthropology, archaeology and computational biology. What's cool is that I get to pick all my favorite parts of all the different fields and bring them together.
Q: What kinds of people benefit the most from your research?
A: Archaeologists, anthropologists, law enforcement, you name it.
When ancient DNA remains are found, or when an anthropologist comes across a mass grave or a grave without a headstone, they use physical anthropology and biological anthropology methods to try to make an identification. My team can come in and identify the physical characteristics of the deceased through genetics, like their skin tone, which you cannot retrieve through bones.
Walsh's research is at the intersection of genetics and forensics, but also includes biology, anthropology, archaeology and computational biology. Photo by Liz Kaye, Indiana University
In forensics, it's used to aid society. Our work is solid and founded on genetics.
When conducting a criminal case, the authorities need some sort of direction. We can give them direction that's science-backed by looking into the DNA that's left behind. I can run some tests and return statistics that say they have blue eyes, or pale skin, or brown hair or Southern European ancestry, or freckles - all based on a scientific calculation.
Q: How should law enforcement use this kind of information?
A: I have done research panels at the National Academy of Science and spoken to investigators, detectives, lawyers, judges, researchers and practitioners on the correct use of this research for casework. This data should not be thrown together and used to start targeting people who fit a profile. Rather, the data should be reviewed independently. It should be used to reshuffle the approach to the investigation. It allows detectives to identify or rank individuals that they may not need to talk to.
My team and I are transparent about the tools we use, what we can gather and what we can't. There are a lot of commercial companies that claim to produce optimized genetic tools and promise results that are not science-backed, particularly in the generation of facial predictions, which are not possible yet. I'm always trying to inform, train and explain not only the science, but also the application.
Q: What's your educational background? How did you know you were interested in genetics?
A: In secondary school, I really enjoyed genetics and biology. However, I had a teacher tell me that forensics is too narrow as a starting point in my university education. She suggested I learn the broad spectrum of biology and get more into a niche as I learn. That was the best advice ever! I even pass that advice down to my students.
I did an undergraduate degree in biochemistry in Ireland. I still had that itch for forensics, so I applied to a master's program in the United Kingdom on DNA profiling. After my master's, I left academia and traveled around Australia.
Eventually, I worked in a DNA sequencing lab but was still searching for something different and wanted to learn more. I found a lab in the Netherlands looking for a Ph.D. student interested in forensics, genetics and appearance. I played a role in changing Dutch legislation to add hair, skin and eye color forensic tools to help their intelligence work for cases in the Netherlands.
Q: What makes IU Indianapolis' Forensic and Investigative Sciences Program unique?
The IU Indianapolis Forensic and Investigative Sciences Program is the only program in the state accredited by the Forensic Science Education Programs Accreditation Commission. Photo by Liz Kaye, Indiana University
Just like my background that spans biology, chemistry and genetics, the program's faculty represent a diverse background of expertise. This allows students to tackle the field from different disciplinary angles such as forensic chemistry and forensic biology.
Q: What is phenotyping?
A: Phenotype is the expression of one's genetics. It can be influenced by environment and other aspects. Your genotype leads to a type of phenotype.
It's not as simple as one gene produces one phenotype. We have a combination of genes that equal a result. When we look at different parts of the genome, we can detect a range of what that phenotype or expression would look like. This includes physical appearance, how much glucose you can break down, and internal or external mechanisms that are programmed in our genetics.
Q: How did your phenotype collection begin?
A: I began in 2014. I knew that if I didn't have a good dataset of genotypic and phenotypic data, then I would not be able to explore the link between the two and find the genes responsible for appearance traits. I would not be able to produce models that were good and reliable. I needed lots of variation in phenotypes and genotypes.
I try to collect as many participants interested in helping us with our research. I keep the DNA database in my lab. It's not connected to the police, and no one can look through it other than me and my lab members. It's locked down on my computers, and in the freezers. Plus, it is anonymized.
Walsh's phenotype collection is made possible by people who have a shared interest in genetics. Photo by Liz Kaye, Indiana University
Without the database and support of the students and people on campus, I could not do any of the work I'm doing to help others. I have had collections done in Lebanon because one of my students went back home and set up a site there. I have collaborators who work in Europe. I have others who work at Penn State, and they have other collaborators who work in South Africa. I have collections that were done in Ireland.
We have this group of individuals with a shared appreciation for genetics, but also the security and protection of our participants. At the end of the day, these participants are helping us make tools that can really impact and help identify missing persons and/or victims of crimes. These participants are the ones making a difference.
Q: Are you still looking for volunteers?
A: Absolutely! Those who are interested can visit our website.
