Scientists Develop New Method to Identify Criminals Using a Single Hair

An Australian research team has developed a method that analyzes proteins contained in a single strand of hair to create a fully unique profile, comparable to a fingerprint.

Known as proteomic genotyping, the technique was developed by two PhD researchers from Edith Cowan University in Western Australia. It is based on detecting genetically variable peptides in isolated hair strands in order to extract genetic information that enables individual identification, chemist Rebecca Taidy writes in the journal Forensic Science International.

The approach relies on the hair proteome — the complete set of proteins expressed in hair. It could prove particularly valuable in cases where DNA analysis is impossible because DNA is missing or degraded. Contrary to what many crime films and television series suggest, a single hair found at a crime scene is usually insufficient to identify a suspect. Reliable identification requires a hair with its root (follicle), which contains the nuclear DNA needed for precise individual profiling.

In real-world crime scenes, however, investigators most often find shed hairs composed of dead, keratinized cells that lack nuclear DNA. When the follicle is absent, analysis can be limited to mitochondrial DNA, which does not allow identification of an individual but only points to maternal lineage and a relatively broad population group.

“Structural proteins persist much longer than DNA under harsh conditions, remaining detectable in tissues long after DNA has become too fragmented for analysis,” said researcher Romy Keane. “Hair is almost always present at crime scenes because it is so common, but its potential has long been underused due to the limitations of traditional microscopic techniques,” she added.

The technique could also help identify victims of natural diseases, potentially exonerating individuals suspected of crimes such as poisoning. | BGNES