Taxonomy table

Information about database structure

Species with valid WoRMS database entries display link to WoRMS.

Press Validate Taxa to load or update taxonomy table.

Sequence table

Information about database structure

Press Validate Taxa to update taxonomy and load sequence table.

You can download these sequences and the corresponding metadata in the “Download selected sequences” tab.

Download selected sequences, taxonomy and metadata

Press Validate Taxa to update taxonomy before downloading

Maximum number of sequences for download: 50,000.If you need more, download the full database.


Protist Ribosomal Reference database (PR2)

Database Date Github


SSU rRNA gene database

The PR2 database was initiated in 2010 in the frame of the BioMarks project from work that had developed in the previous ten years in the Plankton Group of the Station Biologique of Roscoff. Its aim is to provide a reference database of carefully annotated 18S rRNA sequences using eight unique taxonomic fields (from domain to species). At present it contains about 220,000 sequences. A number of metadata fields are available for many sequences, including geo-localisation, whether it originates from a culture or a natural sample, host type etc… The annotation of PR2 is performed by experts from each taxonomic groups. One very important project in this respect is EukRef which has recently decided to merge its effort with PR2. EukRef has built bioinformatics pipelines that have been used during three workshops dedicated to specific taxonomic groups.

Current version

Accessing PR2

About PR2

Core Team

Scientific committee and contributors

Please cite

Related Projects

18S rRNA primer database

The PR2 primer database is a compilation of primers found in the litterature with an in silico analysis against the PR2 database.


The metaPR2 metabarcode database is a compilation of metabarcode datasets processed by the dada2 R package and assigned against PR2.

Questions ?

Report issues

  • Please report any issue on GitHub