Utilizing Predictive Models in Advanced DNA Analysis to Solve Cold Cases and Other Crimes

SAVANNAH, Ga. Crime investigation has undergone a remarkable transformation over the past decade, particularly with the introduction of advanced DNA analysis techniques, including phenotyping. Recently, a 40-year-old cold case in the Lowcountry was resolved thanks to these modern DNA methods.

Parabon NanoLabs, a company specializing in bioinformatics and genetic genealogy, shared insights into how their technology aids law enforcement. Ellen Greytak, Director of Bioinformatics at Parabon, explained that phenotyping allows scientists to predict certain physical characteristics from DNA.

We began with a massive dataset, comprising thousands of participants. We had both their DNA information and detailed records of their physical appearance, including eye color, hair color, skin tone, and 3D facial scans, Greytak said. By analyzing these data points, we can identify genetic differences that influence physical traits.

Parabons system uses approximately 850,000 genetic markers, which can provide information about a persons eye and hair color, ethnicity, and even facial structure. This approach offers law enforcement a more detailed profile than traditional forensic methods. These traits are encoded in your DNA and inherited from your parents, Greytak noted.

However, she cautioned that the predictions are not always perfectly accurate, as some aspects of appearance, such as weight and aging, are not fully determined by DNA. To address this, Parabon works with a forensic artist to create age-progressed images based on their DNA models. The artist applies traditional forensic art methods to visualize how someone might look as they age.

For example, in the 1987 murder case of Margit Schuller in the Lowcountry, Parabon produced a predictive model of the suspects appearance and provided an image showing what he might look like years later. DNA from older cases often presents challenges, such as degradation over decades or samples containing mixed DNA from multiple individuals.

Sometimes we work with DNA that has been stored at room temperature for 40-50 years, so it isnt in perfect condition, Greytak explained. Predictive DNA composites are particularly useful for narrowing suspect pools. One of the key uses is eliminating possibilities. For instance, if investigators were searching for a Hispanic male for years, our analysis might suggest the suspect is a white male with blue eyes, she said.

This information provides new investigative leads, similar to how genealogy can help trace familial connections. Law enforcement can revisit past cases, re-interview potential suspects, or identify victims who were previously unknown. Parabon also offers genealogy services alongside phenotyping, helping connect missing persons or perpetrators with their relatives, thereby narrowing down suspect searches.

Greytak emphasized that bioinformatics doesnt just assist with cold cases; it can also streamline active investigations by reducing unnecessary interviews and focusing resources on the most likely leads.

Author: Maya Henderson