But that’s not accurate, Anex reiterated in an interview. He explained that the team has conducted a
litany of further investigations into the vagaries of protein hair analysis, down to single shafts. The ongoing work—much of it still unpublished—involves looking at the different protein expression in hairs from
different body locations, from the pubic to the scalp, as well as the differences in hair that is long and has
had more exposure to the elements.
The genetically variant peptides, or GVPS, of the proteins reflect the SNPs encoded in DNA, since the
latter has the instructions to make the proteins themselves. But the identifying power is not as strong with
“Some of the headlines said ‘proteins are replacing DNA,’ but that’s not where we’re going with this,”
said Anex. “Hair is pretty indestructible. It can be around for a very long time and the same is true with
tooth and bone.”
The concept in bone was tested, and published earlier this year in the journal Forensic Science
The team took rib bones from 10 recently dead donors, all of European-American ancestry. The team
found a series of 35 different protein markers, using liquid chromatography mass spectrometry
(LCMS) to separate and quantify the multivariant chains of amino acids.
The markers provided enough information to determine RMPS of 1-in- 6, to a best of 1-in-42,000
people. Those are not DNA-caliber numbers, which are often in the realm of millions or billions. The
difficulty with bone is it has a smaller set of GVPs than hair.
“There is inherently less genetic variability in proteins present in bone compared to human hair,” said
Hart. “For purposes of identifying or linking them to evidence, hair proteins are more valuable.”
One particular application of the bone proteomics work would be during a mass casualty situation, like a
Glendon Parker, a biochemist with Lawrence Livermore National Laboratory’s Forensic Science Center, examines a
250-year-old archaeological hair sample that has been analyzed for human identification using protein markers from the
hair. Photo: Julie Russell/LLNL