Eukaryote
Definition
An organism whose cells contain a membrane-bound nucleus and other membrane-enclosed organelles. Humans, animals, plants, and fungi are eukaryotes. Most biological evidence in human forensic casework is eukaryotic in origin.
- Defining feature
- Membrane-bound nucleus and organelles
- Includes
- Humans, animals, plants, fungi
- Contrasted with
- Prokaryotes, which lack a membrane-bound nucleus
- Forensic relevance
- Most human biological evidence is eukaryotic
Common questions
Why does the eukaryote-prokaryote distinction matter in forensic biology?+
It separates human, animal, and fungal cellular evidence, which carries a membrane-bound nucleus holding the nuclear DNA used for STR profiling, from bacterial contamination or bacterial evidence, which lacks that nucleus and requires different molecular targets entirely.
Do all forensic DNA samples come from eukaryotic cells?+
The vast majority of human identification casework does, since blood, saliva, semen, and hair root cells are all eukaryotic, though forensic microbiology occasionally examines prokaryotic bacterial evidence for separate investigative purposes.
Where is the DNA located within a eukaryotic cell that forensic analysis targets?+
Nuclear DNA sits inside the membrane-bound nucleus and is the primary target for STR profiling, while a separate pool of mitochondrial DNA exists outside the nucleus in the mitochondria and is used when nuclear DNA is too degraded.
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...
- Cytoskeleton
- The protein scaffold within eukaryotic cells, composed of actin microfilaments, tubulin microtubules, and intermediate filaments such as keratin. Provides cell shape and...
- 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...