California – A team of researchers at Lawrence Livermore National Laboratory, discovered that human hair‘s protein might be as reliable as DNA to match biological evidence with a person’s identity. This means that collecting and analyzing human hair with certain standards may become the newest forensic technique.
Even though human hair has been used as forensic evidence, it was necessary to reach to the root to get DNA and was that component what allowed the identification of the subject. This research revealed that hair’s proteins are enough by themselves to provide with scientific precision biological data.
Joint efforts
Researchers at seven universities in the United States and Britain, along with the U.S. Energy Department worked in the investigation. The U.S. Defense Department and the Justice Department collaborated with research grants and the lab already spent about $3 million.
The study was called “Demonstration of Protein-Based Human Identification Hair Shaft Proteome” and was published in PLOS One on September 7. Among the authors are Glendon Parker, Tami Leppert, Deon Annex, Jonathan Hilmer, Nori Matsunami, Lisa Baird, and others.
The team used Protein-Base Identification Technologies. They collected hair samples from modern subjects with different ethnicity and samples from ancient human remains.
A relevant ancestral background was discovered through the study of the subjects’ hair structure and protein composition, and even with significantly degraded hair samples, genetic analysis was possible.
How does it work?
Hair is composed of different kind of proteins. Proteomics, the study of proteins produces by genes, may identify genetic mutations and genetic material enough to identify or to exclude people involved in a crime.
This method eliminates visual comparisons on hair structure and uses the proteomic investigation to measure mutations in amino acids, a relevant component in proteins. The protein structure of human hair studied this way could allow the precise identification of unique genetic components without using DNA.
In the investigation, about 200 hair protein markers were identified and “using those markers; unique patterns can be found to distinguish one person from a population of one million inhabitants,” suggested Glendon Parker, a member of the team of researchers.
Using tissue procurement, proteomic data acquisition and identification of single amino acids containing peptides, the researchers validated and identified genetically variant peptides.
However, there are still many unanswered questions about the proteins in human hair. For example, staff from the Forensic Science Graduate Program at the University of California consider it is still unknown how are proteins affected by the environment and diets, as well as why the protein markers are unique and different even in identical twins with matching DNA profiles. But this last consideration may lead to human hair as an even more accurate forensic method to identify the biological material.
A new way in forensic science
This new method allows the expansion of the range of forensic tools to determine the identity of persons involved in a crime scene. So far, scientists were entirely dependent on DNA collection and profiling, but this mechanism may open up new possibilities.
We are in a very similar place with protein-based identification to where DNA profiling was during the early days of its development, this method will be a game-changer for forensics, but many steps remain before it is completely validated,” said Brad Hart, director of the national laboratory’s Forensic Science Center.
The goal is to design a scientifically precise method to correctly analyze forensic evidence in crime scenes, separate from the DNA testing but complementary to it.
Source: Journal PLOS One