NCJ Number
225663
Journal
Forensic Science International: Genetics Volume: 3 Issue: 1 Dated: December 2008 Pages: 32-36
Date Published
December 2008
Length
5 pages
Annotation
Because degraded DNA is believed to originate from epidermal cells and to be responsible for the phenomenon of the retrieval of an individual’s genetic profile from touched objects, the current study conducted a morphological and immunohistochemical investigation of nuclear DNA in differentiating keratinocytes in the skin, as well as a genetic analysis of DNA on swabs of human skin.
Abstract
The findings indicate that it is possible that DNA fragments on touched objects may originate from the epidermal cells of the cornified layer of the skin that are constantly sloughed off and leave from the skin surface with sweat. It is conceivable that a genetic profile might be retrievable from any object touched by an individual, because sweat deposited on the object could contain the trace DNA. Immunoelectron microscope analysis showed that single-stranded DNA was found both in the cornified layer of the skin and in swabs. Real-time-PCR assay indicated that the DNA in the swabs was derived from the human DNA. Electron microscopic analysis of shadow-cast showed the presence of small DNA fragments in the swabs. The descriptions of material and methods address the samples used; the transmission electron microscopy and platinum shadow-casting used in the morphological studies; the light microscope, transmission electron microscopy, human skin, and cotton-swabbed objects used in the immunohistochemistry; and the DNA extraction, agarose gel electrophoresis, real-time-PCR assay, and amplification and eletrophoresis of STRs used in genetic studies. 1 table, 7 figures, and 11 references