Prokaryote
Definition
An organism whose cells lack a membrane-bound nucleus and organelles. Bacteria and archaea are prokaryotes. They are relevant to forensic biology in microbiome-based methods and in cases involving bacterial contamination of evidence.
- Domains
- Bacteria and Archaea
- Nucleus
- Absent, no membrane-bound organelles
- Genome location
- Nucleoid, a single circular chromosome
- Forensic relevance
- Microbiome profiling, PMI estimation, contamination source tracing
Common questions
How does a forensic microbiome study use prokaryotes?+
Bacterial community composition on skin, soil, or a decomposing body shifts in a fairly predictable way over time and by location, so sequencing the prokaryotic population can help estimate postmortem interval or geographic origin of trace material.
Can bacterial DNA interfere with human DNA profiling?+
Yes. Heavy bacterial contamination of a sample can compete for reagents in PCR and reduce the yield of human-specific STR amplification, which is why swabs from decomposed remains are handled with contamination controls.
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...
- 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...