Human hair shaft proteomic profiling: individual differences, site specificity and cuticle analysis
Chelsea N. Laatsch,
Blythe P. Durbin-Johnson,
David M. Rocke,
Sophie Mukwana,
Abby B. Newland,
Michael J. Flagler,
Michael G. Davis,
Richard A. Eigenheer,
Brett S. Phinney,
Robert H. Rice
Affiliations
Chelsea N. Laatsch
Forensic Science Graduate Program and Department of Environmental Toxicology, University of California, Davis, CA, USA
Blythe P. Durbin-Johnson
Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
David M. Rocke
Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
Sophie Mukwana
Biotech Forensics, Nairobi, Kenya
Abby B. Newland
Procter & Gamble, Mason Business Center, Mason, OH, USA
Michael J. Flagler
Procter & Gamble, Mason Business Center, Mason, OH, USA
Michael G. Davis
Procter & Gamble, Mason Business Center, Mason, OH, USA
Richard A. Eigenheer
Proteomics Core Facility, University of California, Davis, CA, USA
Brett S. Phinney
Proteomics Core Facility, University of California, Davis, CA, USA
Robert H. Rice
Forensic Science Graduate Program and Department of Environmental Toxicology, University of California, Davis, CA, USA
Hair from different individuals can be distinguished by physical properties. Although some data exist on other species, examination of the individual molecular differences within the human hair shaft has not been thoroughly investigated. Shotgun proteomic analysis revealed considerable variation in profile among samples from Caucasian, African–American, Kenyan and Korean subjects. Within these ethnic groups, prominent keratin proteins served to distinguish individual profiles. Differences between ethnic groups, less marked, relied to a large extent on levels of keratin associated proteins. In samples from Caucasian subjects, hair shafts from axillary, beard, pubic and scalp regions exhibited distinguishable profiles, with the last being most different from the others. Finally, the profile of isolated hair cuticle cells was distinguished from that of total hair shaft by levels of more than 20 proteins, the majority of which were prominent keratins. The cuticle also exhibited relatively high levels of epidermal transglutaminase (TGM3), accounting for its observed low degree of protein extraction by denaturants. In addition to providing insight into hair structure, present findings may lead to improvements in differentiating hair from various ethnic origins and offer an approach to extending use of hair in crime scene evidence for distinguishing among individuals.
