Development of a Protein-based Human Identification Capability from a Single Hair.

Area of Science:

• Forensic Science
• Biochemistry
• Genetics

Background:

• Shed human hair is crucial for forensic identification but lacks root nuclear DNA.
• Existing methods like microscopic analysis and mitochondrial DNA sequencing have limitations.
• Genetic variations in hair proteins offer a new avenue for identity markers.

Purpose of the Study:

• To develop a novel method for analyzing genetically variant peptides (GVPs) in single human hairs.
• To establish a new set of identity markers for forensic applications.
• To assess the applicability of GVP profiling for individual identification.

Main Methods:

• Developed a method to completely dissolve single hairs using heat, ultrasonication, and surfactants.
• Proteins were digested, and genetically variant peptide (GVP) profiles were generated.
• Utilized high-resolution nanoflow liquid chromatography-mass spectrometry and a novel exome-driven bioinformatic approach.

Main Results:

• Successfully identified 6519 unique peptides from single hairs (25 mm).
• Confirmed the presence of 57 genetically variant peptides (GVPs).
• Calculated random match probabilities for GVPs ranging from 2.6 × 10^-2 to 6.0 × 10^-9.

Conclusions:

• The new bioinformatic strategy enables GVP analysis in forensic samples.
• This protein-based approach provides powerful new markers for human identification.
• The method demonstrates significant potential for distinguishing individuals in forensic contexts.