DNA Phenotyping: Revealing the Faces of Killers


What if DNA found at a crime scene could reveal the face of a killer? We’re very nearly there, and getting closer ever day thanks to the technology behind DNA Phenotyping.

What is DNA Phenotyping?

Our DNA contains our unique genetic code; it’s the blueprint our bodies are built from. This includes genetic instructions for our hair color, eye color, face shape and everything else. DNA phenotyping is the process of predicting a person’s physical appearance based on their genetic code. It’s not an exact science – and it will likely never reveal a picture-perfect image – but DNA Phenotyping gets very close. It’s already come close enough to help law enforcement solve cases, and it may one day be one of the first steps in an investigation which helps detectives to narrow their field of suspects to only those who match the phenotype composite.


What can DNA Phenotyping Reveal?

With our current technology DNA Phenotyping can reveal ethnicity, gender, eye color, hair color, height and even age; although the current accuracy on the last four is not 100%. It can also be used to project a general face shape and technology is in the works which may identify baldness, hair texture (curly vs. straight) and the shape of a suspect’s teeth. Put together, all this forms a “ball-park” picture than can at least give law enforcement an idea of who they should be looking for.


What DNA Phenotyping Can’t Do?

DNA Phenotyping cannot give a completely accurate picture of anyone. It can only produce the most likely, general appearance based on the subject’s DNA. It also cannot account for things like dyed hair, broken noses or dental work; things which may change a suspect’s appearance but will never be reflected in their DNA.

How is DNA Phenotyping Being Used in Forensics?

DNA Phenotyping has already been used to assist law enforcement in case investigations. Last year police in South Carolina publicly released a phenotype composite photo of a suspect they believe may have murdered a woman and her three-year-old daughter. There were no witnesses to the crime, and the suspect’s DNA could not be matched to anything in the database. The phenotyped image was all they had to go on.  The Toronto police force has ordered phenotyping on 29 samples to help them solve open cases, and more law enforcement agencies may follow suit once the technology becomes more widespread. There are several companies devoted to offering phenotyping, and they do currently aid law enforcement in their investigations. For more information, you can check out Parabon Snapshot, Identitas, and Illumina. Unfortunately, phenotyping is still a developing science; there is a long way to go before it is commonly used.


The (Likely) Uphill Legal Battle Facing DNA Phenotyping

Like every new technology, DNA Phenotyping must undergo strenuous vetting before it can be concluded that it is both accurate and legally sound. At present many scientists take issue with the fact that phenotyping can, at best, provide a general outline for what a person may look like. Additionally, there is the question of accuracy. Traits like height are only about 80% dependent on genetics, there is still a great deal of variation possible. Eye color is called into question too; brown eyes and blue eyes are fairly easy to predict, but colors like hazel are far more difficult to phenotype. There is also the legal issue of phenotyping possible medical conditions. A person’s DNA may reveal a number of diseases, or even their likelihood of contracting something like cancer; all of which is legally protected information. Thankfully crime scene DNA is legally termed “abandoned material” and as such, anything goes. Scientists are free to explore every genetic possibility in their attempt to bring perpetrators to justice.

Meet the Researchers Behind the Technology

Forensic phenotyping is a growing field, made possible by the hard work of scientists like Dr. Walsh at Erasmus University MC Medical Center in the Netherlands, who helped develop the HIrisPlex technology used to predict eye color. In the United States Dr. Susan Walsh, an assistant professor of biology at Indiana University/Purdue University Indianapolis recently received a $1 million grant from the Department of Justice to develop phenotyping tools which can be used to solve cases. It’s not just scientists who are taking DNA to the next level either, Dr. Dewey-Hagborg, Assistant Professor of Art and Technology Studies at the Art Institute of Chicago, even created an art exhibit where she combined 3D printing and phenotyping to generate the faces of strangers based on abandoned DNA. With so many exciting new technologies on the horizon it’s a great time to study forensics. If you’re thinking about getting your forensic science degree online, be sure to check out our list of top schools and scholarships for forensic science students.