Assessing Single-Source Reproducibility of Human Head Hair Peptide Profiling from Different Regions of the Scalp

• Published in: Forensic science international : genetics 2020-09, Vol.50
• Main Authors: Lawas, Maria, Jones, Katherine F., Mason, Katelyn E., Anex, Deon S., Carlson, Traci L., Forger, Luisa V., Eckenrode, Brian A., Hart, Bradley, Donfack, Joseph
• Format: Article
• Language: English
• Subjects: BASIC BIOLOGICAL SCIENCES; genetically variant peptide (GVP); Hair shaft; liquid chromatography tandem mass spectrometry (LC-MS/MS); microscopical hair comparison; non-synonymous single nucleotide polymorphisms (nsSNPs); single amino acid polymorphism (SAP)
• ISSN: 1872-4973; 1878-0326

Neither microscopical hair comparisons nor mitochondrial DNA sequencing alone, or together, constitutes a basis for personal identification. Due to these limitations, a complementary technique to compare questioned and known hair shafts was investigated. Recently, scientists from Lawrence Livermore National Laboratory's Forensic Science Center and other collaborators developed a peptide profiling technique, which can infer non-synonymous single nucleotide polymorphisms (SNPs) preserved in hair shaft proteins as single amino acid polymorphisms (SAPs). In this study, peptide profiling was evaluated to determine if it can meet forensic expectations when samples are in limited quantities with the possibility that hair samples collected from different areas of a single donor’s scalp (i.e., single source) might not exhibit the same SAP profile. The average dissimilarity, percent differences in SAP profiles within each source, ranged from 0% difference to 29%. This pilot study suggests that more work is needed before peptide profiling of hair can be considered for forensic comparisons.