The mechanism whereby DNA is transferred from the skin is
complicated. Wickenheiser [2] states that skin cells are nucleated.
Other authors state skin epithelial cells differ morphologically
from other epithelial type cells from the vagina and mouth because
they lack nuclei and are keratinised [5]. Wickenheiser [2] does
explain that through the sloughing process skin cells are exposed
to large numbers of DNA bearing cells en route to the skins surface.
This may load the skin epithelial cells that may otherwise be a poor
source, with DNA. Thus the cellular origin of the DNA on the skin
may not be as simple as being attributed to skin cells alone.
Wickenheiser [2] proposes that transmission of DNA may result
from the hands/fingers acting as vectors for other cells and that it is
cells that originate from the mouth, nose, eyes or any other source
of DNA rich cells that are contributing to the profile.