16S rRNA Gene
Definition
The gene encoding the 16S ribosomal RNA subunit present in all bacteria and archaea. Conserved regions allow universal amplification; hypervariable regions (V1-V9) differ between taxa and enable identification to genus and often species level.
- Present in
- All bacteria and archaea
- Structure
- Conserved regions plus hypervariable V1-V9 regions
- Typical resolution
- Genus level, often species level
Common questions
How do the conserved regions make universal primers possible?+
Conserved stretches of the gene are nearly identical across bacterial and archaeal taxa, so a single primer pair can bind and amplify the gene from a very wide range of organisms without needing a different primer for each species.
What is the practical difference between the 16S rRNA gene and the 16S rRNA molecule?+
The gene is the DNA sequence in the genome that is targeted and amplified for sequencing, while the rRNA molecule is the RNA transcript actually built into the bacterial ribosome; forensic work analyzes the DNA gene, not the ribosome itself.
Related terms
- Amplicon Sequencing
- A sequencing approach where a specific locus (here the 16S hypervariable region) is amplified from all members of a microbial community and...
- Community State Type (CST)
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- Microbiome
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- OTU / ASV
- Operational Taxonomic Unit (OTU) and Amplicon Sequence Variant (ASV) are the units of microbial diversity in 16S data. OTUs cluster reads at...
- Shotgun Metagenomics
- Sequencing all DNA in a sample rather than just the 16S amplicon. Provides taxonomic resolution beyond 16S and can characterise viruses and...