Science Vs

DNA and the Smell of Death

Oct 21, 2016

51:49

Snipd AI

Multiple experts specializing in DNA evidence and the smell of death discuss the reliability of emerging DNA evidence and the fascinating world of cadaver dogs in crime investigations. They explore the complexities and limitations of DNA evidence, the challenges in interpreting DNA mixtures, and the use of cutting-edge forensic technology. They also delve into the science behind how bodies decompose and release volatile organic compounds, and discuss the training methods and reliability of dogs trained to find human remains. The chapter emphasizes the importance of exposing baseless junk science in the field of forensics.

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Quick takeaways

Trace DNA analysis in forensic science has limitations in interpreting small samples, as seen in the Amanda Knox trial.

Interpreting DNA mixtures with more than two individuals is complex, with computer programs lacking extensive independent testing, as highlighted in the Casey Anthony trial.

Deep dives

Reliability of Trace DNA Evidence

Trace DNA, which refers to a small amount of DNA found in a sample, has become a valuable tool in forensic science. However, when there is only a limited amount of DNA, the results can be less reliable due to the amplification of noise during the copying process. While scientists have made significant advancements in analyzing trace DNA, it is crucial to acknowledge the limitations of interpreting such small samples. The Amanda Knox trial serves as an example of the challenges in using trace DNA as a forensic tool, as problems with the interpretation of DNA evidence were one factor leading to the acquittal of the accused individuals.

Introduction

2min

Exploring the Challenges of DNA Evidence

21min

The Limitations of Technology in Forensics

2min

Detecting the Scent of Death

6min

Dogs trained to find human remains

16min

The Importance of Exposing Baseless Junk Science

3min

In these cases, emerging DNA evidence and the smell of death (yes, really) pushed the boundaries of what was technologically possible. But how reliable are they? To find out, we go to a body farm and talk to Assoc. Prof. Joan Bytheway, Asst. Prof. Sheree Hughes-Stamm, Matt Young, Dr. Arpad Vass, and Asst. Prof. Donovan Haines.

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Credits

This episode has been produced by Wendy Zukerman, Shruti Ravindran, Diane Wu,and Heather Rogers. Our senior producer is Kaitlyn Sawrey. Edited by Annie-Rose Strasser and Caitlin Kenney. Fact checking by Michelle Harris. Thanks to Joseph Lavelle Wilson, Will Doolan and Beth McMullen. Sound design and music production by Matthew Boll, mixed by Martin Peralta and Matthew Boll Music written by Bobby Lord.

Selected References

2009 National Academy of Sciences and 2016 President’s Council of Advisors on Science and Technology reports on forensic science.

How DNA is transferred in trace evidence. Report on error rates in DNA forensic analysis.

Study that showed dogs could pick up the smell of a corpse 667 days later.

Call to arms on improving forensic science: editorial.

Scent of death - Belgian paper that found three out of four of Dr Arpad Vass' “human specific markers” in other animals.

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