ForensicsForensic Proteomics: Going Beyond DNA Profiling

Published 13 February 2020

A new book details an emerging forensic method that could become as widespread and trustworthy as DNA profiling. The method is called mass-spectrometry-based proteomics, which examines the proteins that make up many parts of living things. These proteins exist in unique combinations in everything from blood cells and clothing fibers to certain types of medicine and the diseases they fight. Because proteomics analyzes these proteins directly, forensic proteomics can fill in when DNA is missing, ambiguous, or was never present to begin with.

A new book edited by a PNNL biochemist details an emerging forensic method that could become as widespread and trustworthy as DNA profiling.

The method is called mass-spectrometry-based proteomics, which examines the proteins that make up many parts of living things. These proteins exist in unique combinations in everything from blood cells and clothing fibers to certain types of medicine and the diseases they fight. Because proteomics analyzes these proteins directly, forensic proteomics can fill in when DNA is missing, ambiguous, or was never present to begin with.

In the book, Applications in Forensic Proteomics: Protein Identification and Profiling, PNNL’s Eric Merkley gathers articles by leaders in the field to provide a snapshot of the method’s promising applications and outlines ways to develop the method to meet stringent legal standards for scientific testimony.

“This is an effort to crystallize a community of experts in the field,” said Merkley. “With the right research focus and rigorous approach at this early stage, in 10 years, proteomics could be routinely adopted in the courtroom to address critical unanswered questions in forensic science.”

Forensic science analyzes evidence to answer courtroom questions like “Who was here?” and “What were they doing?” The trouble is, much of what people consider forensic science isn’t actually approached very scientifically”. Without a true scientific approach, pattern recognition techniques like fingerprint or hair analysis are increasingly challenged or criticized, leading some judges to throw these methods out of court.

PNNL notes that the exception to this forensic black eye is DNA profiling, which has a stronger statistical foundation and more scientific validation. However, when DNA isn’t enough, proteomics can fill in.

For example, forensic proteomics can provide meaningful evidence in a search centered on a protein-based toxin, drug, or sports doping hormone. It can reveal clues about whether a disease occurred naturally or as the result of a biological attack. And forensic proteomics can aid investigations after DNA has identified which individuals were present, but not what type of tissue, fluid, or fingerprint residue they left behind.

A Method of Mass Detection
Scientists already detect certain proteins when they are testing for things like anthrax or other bioweapons by knowing what they are looking for in advance. To target the suspected protein, researchers develop an antibody that binds to one specific protein and gives a positive or negative reading, much like the lines on a home pregnancy test.