Often a crime scene is comprised of teeth, hair, and not much else. So, how can the police determine what happened when there is seemingly little evidence? Professors in the department of environmental toxicology at the University of California, Davis (UC Davis), Glendon Parker and Robert Rice and their forensic science teams believe that even nominal evidence can help link a suspect/perpetrator to a crime scene. The key is the use of proteomics, which can be used to determine human and ancestral classification. Julia Yip, a 2018 UC Davis graduate forensic science program says, "Proteomics involves the large-scale analysis of the protein component of a cell, tissue or an organism."
Zachary Goecker, a fifth-year doctoral student in pharmacology and toxicology at UC Davis says, "The joint effort of both the Rice and Parker labs have resulted in sex estimation from teeth, human identification from skin, human identification from hair, and even work with ancient bone."
In order to study proteins, researchers analyze proteins in tissue and use mass spectrometry to analyze the same and determine the mass-to-charge ratio of ions. Says Dr. Parker, "What we do is we discover, characterize and work at ways to detect a certain set of peptides that change as a result of someone’s genetics. These are single amino acids that are swapped out. Then we can get a pretty big chunk of information that should have been in their DNA."
According to Dr. Parker, conventional forensic science techniques often fall short of being able to determine information from hair, bone, fingerprints, and teeth, and that’s why Dr. Parker has focused on this area of forensics. The analysis of human hair under a microscope was long used to place a suspect at a crime scene, but Dr. Rice stresses how ineffective that method is, “There have been a lot of people convicted of crimes because their hair looked the same as the hair found in the crime scene. It turns out many of those people have now been exonerated. Those hair identifications, nobody believes them anymore, and so you have a substantial amount of people who should not be imprisoned.”
Parker, Rice, and their teams have made substantial advances using proteomics to help advance forensic science techniques that are reliable and can be used in the field. Their research is ongoing and very promising.