SEATTLE - Hair is made of proteins that are constructed using the blueprints from the DNA of individuals. Forensic science has been looking at the hardy structure of the hair shafts everyone sheds as being a potential game-changer at crime scenes and archaeological sites, where more-fragile DNA is not available.

The forensic value of putting those proteins under the microscope could prove to help investigators of the future, according to the latest scientific findings, a poster presented at last week’s American Academy of Forensic Sciences conference showed.

The University of California, Davis scientists found there were more differences between hairs of different people than the hairs of the same person from different parts of their body.

But the technique needs improvement to increase its discriminatory power, they add.

“We demonstrate that (genetically variant peptides) profiles from different body locations in an individual are more similar than profiles between different individuals,” they write. “Nevertheless, some GVPs are clearly not detected in some profiles, producing false negatives.”

The team looked at hairs from four different body locations in five different individuals. The locations of the hair shafts were from the scalp, the beard, the pubic area and the armpit.

The samples were processed with sodium dodecanoate, and finally digested with trypsin.

The isolated peptide mix was then assessed by liquid chromatography-mass spectrometry. The resulting datasets were organized through the Global Proteome Machine. Those datasets were screened for previously known and identified GVPs, they report.

The researchers concluded that the hairs from a single person’s body—for instance, the pubic and scalp shafts—were more similar than the hairs from two different people.

“Based on this data we conclude that these changes are due to chemical and analytical factors and not underlying biological effects,” they write.

The UC Davis team adds that new methods in hair processing are likely to improve differentiation of the smallest characteristics of the hair proteins.

“We hypothesize that these new methods will decease false positive rates, increase the differences between individuals, and further decrease the differences in profiles between different body locations,” they write.

Members of the same team were also involved in two previous major studies on the hair proteomics question.

Last summer, seven of the same authors from UC Davis wrote in the journal Proteomics that their investigation of monozygotic twins showed that it could “provide a framework for developing quantitative statistical estimates of personal identification that increase the value of hair shaft evidence.”

Four of the UC Davis team were also involved in a major collaboration with Lawrence Livermore National Laboratory demonstrating the potential forensic value of hair proteins in the journal PLoS ONE in September 2016