Corneocyte
Definition
A terminally differentiated, anucleate cell forming the outermost skin layer (stratum corneum). Corneocytes shed continuously. Nucleated cells from deeper epidermal layers are also deposited during contact and are the primary source of DNA in touch samples.
- Layer of origin
- Stratum corneum, outermost skin
- Nucleus
- Anucleate (no nucleus)
- Shedding
- Continuous
- DNA yield
- Low; nucleated deeper-layer cells yield more DNA
Common questions
If corneocytes have no nucleus, where does touch DNA actually come from?+
Mostly from nucleated cells of the deeper epidermal layers that get dislodged and deposited alongside the shed corneocytes during contact, plus DNA released from cell fragments and other biological material such as sweat and sebum.
Why does touch DNA recovery vary so much between individuals and contacts?+
The proportion of nucleated versus anucleate cells transferred depends on grip pressure, skin condition, and how much friction the contact involved, so a firm, prolonged grip typically sheds more nucleated material than a brief light touch.
Related terms
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- Low Copy Number (LCN) DNA
- An approach to analysing low-template samples by increasing the number of PCR amplification cycles, typically to 34 cycles. Increases sensitivity but also...
- Secondary Transfer
- The movement of a glass fragment from a primary surface (which contacted the broken glass) to a secondary surface (which contacted the...
- Stochastic Effect
- A random sampling artefact that occurs at very low template quantities. Examples include allelic dropout (an allele fails to amplify), allelic drop-in...
- Touch DNA
- Minute quantities of epithelial cells transferred by skin contact with a surface, without leaving a visible stain. Collected by swabbing contact points...