Cytoskeleton
Definition
The protein scaffold within eukaryotic cells, composed of actin microfilaments, tubulin microtubules, and intermediate filaments such as keratin. Provides cell shape and mechanical strength. In hair and nail cells, the keratin intermediate filament network survives cell death and forms the physical fabric of these evidence types.
- Components
- Actin microfilaments, tubulin microtubules, intermediate filaments
- Function
- Cell shape and mechanical strength
- Forensic relevance
- Keratin filaments survive cell death in hair and nail
- Field
- Cell biology for forensic science
Common questions
Why does hair remain structurally intact long after the cells that produced it have died?+
The keratin intermediate filament network that made up the cytoskeleton of the hair-forming cells is cross-linked and chemically stable, so it persists as the physical scaffold of the hair shaft well beyond the death of the living cells that assembled it.
Does the cytoskeleton contain DNA that can be typed from a hair shaft?+
No. The cytoskeleton itself is a protein structure, not genetic material, so hair shaft DNA typing instead targets whatever mitochondrial DNA or trapped nuclear material remains in the shaft, independent of the keratin scaffold.
Related terms
- Chromatin
- The complex of nuclear DNA wound around histone proteins in the nucleus. In forensic DNA extraction, chromatin must be disrupted to release...
- Eukaryote
- An organism whose cells contain a membrane-bound nucleus and other membrane-enclosed organelles. Humans, animals, plants, and fungi are eukaryotes. Most biological evidence...
- Mitochondrial DNA (mtDNA)
- DNA located in mitochondria rather than the cell nucleus. Present in hundreds to thousands of copies per cell, making it recoverable from...
- Nuclear DNA (nDNA)
- The genomic DNA housed in the cell nucleus, packaged as 46 chromosomes in human somatic cells. The primary target for STR profiling...
- Prokaryote
- An organism whose cells lack a membrane-bound nucleus and organelles. Bacteria and archaea are prokaryotes. They are relevant to forensic biology in...