NCJ Number
225600
Journal
Journal of Forensic Sciences Volume: 53 Issue: 6 Dated: November 2008 Pages: 1363-1366
Date Published
November 2008
Length
4 pages
Annotation
Since the amount of tissue attached to a telogen hair root usually determines whether that hair is suitable for nuclear DNA typing methods or mitochondrial DNA (mtDNA) typing methods, this study used transmission and scanning electron microscopy in order to characterize the content of the material attached to telogen club roots, so as to determine which tissues might be most suitable for nuclear DNA typing.
Abstract
The tissues analyzed were found to consist of keratinized remnant follicle, nonnucleated epithelial cells, nucleated epithelial cells, and trichilemmal keratin. These findings are consistent with the known principles of hair follicle regression. The hair follicle consists of several concentric layers of cooperating cell types that support and maintain the growing thread of protein recognized as hair. Generally, the numerous differentiated layers of the follicle can be categorized as inner root sheath (next to the hair shaft cuticle), outer root sheath, and dermal sheath. During catagen, or regression phase, the inner root sheath completely disintegrates through apoptosis, and the telogen club is formed in the upper hair follicle near the level of the sebaceous gland duct. Telogen hair root clubs are frequently found with a nipple of tissue at the end. The nipple is primarily composed of the connective tissue follicle from the outer root sheath. No nuclei were observed in the nipple structure or in the trichilemmal structure around the club. It can be expected that telogen hair roots with tissue superior or inferior (excluding nipple structures) to the club to be most suitable for nuclear DNA typing, because these cells originate in the upper outer root sheath and dermal sheath. These areas of the follicle are unaffected by the apoptotic/keratinization changes that occur during catagen phase. 10 figures and 10 references