January 31, 2025

#326 How DNA Solves Crimes: The Forensic Science Behind True Crime

45 minutes

True crime dominates the podcasting world, but what about the genetic aspects behind these cases? In this episode of DNA Today, we dive into the pivotal role of DNA in forensic science with Dr. Henry Erlich, a pioneer in DNA analysis and a key figure in developing polymerase chain reaction (PCR) technology. His work has transformed the criminal justice system, from solving cases to overturning wrongful convictions.

Dr. Henry Erlich has authored over 450 publications and spent decades applying DNA analysis to criminal investigations, missing persons cases, and ancestry research. His lab performed the first DNA case in the US and, in 1988, the first DNA exoneration. Erlich was the Director of the Department of Human Genetics and Vice-President of Discovery Research for Roche Molecular Systems, Inc until 2013. He is currently a Senior Scientist at Benioff Children’s Hospital Oakland Research Institute. He has published > 450 articles and is the recipient of numerous awards.

After reading his book Genetic Reconstruction of the Past, I had countless questions about how PCR reshaped the justice system, its impact on exonerations, and the ethical implications of forensic DNA databases.

Trigger Warning: This episode contains discussions of murder and sexual assault, which may not be suitable for young listeners.

Topics Covered:

The development of PCR technology and its revolutionary impact on forensic genetics

How PCR outperformed older methods like RFLP in criminal case investigations

Pennsylvania vs. Pestinikas (1986), the first criminal case using DNA analysis

Key forensic DNA terms explained: inclusion, match, exclusion, and random match probability

The role of DNA evidence in exonerations and wrongful convictions

How forensic labs analyze DNA from multiple individuals at crime scenes

The establishment of the FBI’s National DNA Index System (NDIS) and who is included

The ethical concerns surrounding partial DNA matches and familial searching

How public DNA databases like GEDmatch helped identify the Golden State Killer

Dr. Erlich’s insights into the O.J. Simpson case and its impact on public perception of forensic DNA

Resources and Links:

Read Genetic Reconstruction of the Past by Dr. Henry Erlich

Explore the National DNA Index System (NDIS) and CODIS

The Innocence Project: Fighting wrongful convictions with DNA evidence

GEDmatch and its role in forensic investigations

Get ready, genetic nerds—another brand-new episode of DNA Today drops this Friday! You can always count on us to deliver fresh content every Friday.

While you wait, why not dive into our library of over 300 episodes? Binge them all on Apple Podcasts, Spotify, our website, or wherever you love to listen—just search “DNA Today.”

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DNA Today is hosted and produced by Kira Dineen, MS, LCGC, CG(ASCP)CM . Our Video Lead is Amanda Andreoli. Our Social Media Lead is Kajal Patel. Our Outreach Intern is Liv Davidson. And our logo Graphic Designer is Ashlyn Enokian, MS, CGC.

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By Kira Dineen

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