ISSN: 0022-1198
CODEN: JFSCA
Published Online: 1 March 1998
Page Count: 10

Evaluation of the Human Hair Root for DNA Typing Subsequent to Microscopic Comparison
Linch, CA
Trace Evidence Analysts respectively, Criminal Investigation Laboratory, Southwestern Institute of Forensic Sciences, TX

Prahlow, JA
Medical Examiner, assistant professor/forensic pathologist, Southwestern Institute of Forensic Sciences, U.T. Southwestern Medical Center, TX

Smith, SL
Trace Evidence Analysts respectively, Criminal Investigation Laboratory, Southwestern Institute of Forensic Sciences, TX

(Received 20 May 1997; accepted 1 August 1997)

Abstract

Telogen human hairs are one of the most common useful evidence findings at crime scenes and/or on homicide victims. Occasionally, the microscopic characterization of the found telogen hair is the only physical evidence association to a victim or suspect. Recently efforts to characterize these hairs by mitochondrial DNA (mtDNA) methods have progressed. The nature of the telogen hair root morphology and ultrastructure has, however, been largely ignored. Examiners have recognized these hairs are unlikely to be typable by nuclear DNA (nuDNA) methods. Most forensic biologists have little knowledge of the complex cellular composition of anagen, catagen, and telogen hair roots or their morphogenesis. This paper reviews ex situ human hair root morphology as it relates to the likelihood of successful nuclear DNA typing. Dermatology texts of hair root morphology always demonstrate their microscopic appearance in the skin. This study investigates the use of fluorescence in situ hybridization (FISH) methods to sex type telogen head hairs, and it further investigates hair root morphology as it relates to the potential nuclear DNA content of evidence hairs.

There is a need for the use of appropriate, consensus terminology for describing hair root morphology. There is also a need for standardized laboratory light microscopic methods in evaluating a hair root for DNA typing. FISH was found to be an unsuitable technique for sex determination of telogen hair clubs. It was determined that anagen/catagen hair roots without translucent sheath material are excellent candidates for nuDNA PCR-based typing and that hairs with telogen club root material only should not be submitted for nuDNA typing attempts.

Keywords:
forensic science, hair root morphology, hair growth phases, apoptosis, transmission electron microscopy, fluorescence in situ hybridization, sex determination, hairs, mitochondrial DNA typing, DNA typing, HLA-DQA1, GYPA, HBGG, D758, GC, LDLR

Paper ID: JFS16137J
DOI: 10.1520/JFS16137J
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