Summary
Comparing a conserved ribosomal gene to identify and classify bacteria and archaea.
In depth
The 16S gene has conserved regions for primer binding and variable regions for identification. Carl Woese used rRNA to define three domains. Operational taxonomic units or ASVs are used in analysis.
16S sequencing gives relative abundance but not function. PCR bias can distort. Resolution is often to genus level.
Key idea: ribosomal genes serve as molecular chronometers.
16S rRNA is about 1500 bases long, present in all bacteria and archaea, functionally constant and with regions of different variability. Sequences are grouped into OTUs or amplicon sequence variants, and matched against databases (SILVA, Greengenes, RDP). It generally resolves genus, sometimes species, but not strain. Gene copy number varies (from 1 to 15), affecting abundance estimates.
Woese's sequencing of rRNA catalogues in the 1970s overturned the five kingdom view and led to the three domain tree. The eukaryotic equivalent is 18S rRNA, and fungi use the ITS region. Whole-genome sequencing now gives more detailed identification.
Example: hospital labs use 16S sequencing to identify bacteria that cannot be identified by usual tests.
Frequently asked questions
What is 16S rRNA Sequencing?
Comparing a conserved ribosomal gene to identify and classify bacteria and archaea.
Which area of biology covers 16S rRNA Sequencing, and how advanced is it?
16S rRNA Sequencing is one of the 54 topics in Microbiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Metagenomics, Microbial Taxonomy, Horizontal Resistance Spread.
Can you give an example of 16S rRNA Sequencing?
Gut studies compare microbial composition between healthy and sick people.
What should I learn before 16S rRNA Sequencing?
Work through the Beginner topics in Microbiology first, such as Microorganisms, Bacteria, Archaea, then return to 16S rRNA Sequencing. Advanced topics assume the Intermediate vocabulary.
What topics are related to 16S rRNA Sequencing?
The closest topics to 16S rRNA Sequencing are Metagenomics, Microbial Taxonomy, Horizontal Resistance Spread, Bacterial Genetics. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand 16S rRNA Sequencing?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for 16S rRNA Sequencing. To practise the whole of Microbiology, use the Microbiology quiz.
How is 16S rRNA Sequencing different from Metagenomics?
16S rRNA Sequencing: Comparing a conserved ribosomal gene to identify and classify bacteria and archaea. Metagenomics: Sequencing DNA directly from environmental samples to study unculturable microbial communities. Read both side by side and note what each one explains.
How should I study 16S rRNA Sequencing step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Metagenomics and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.