Accession Numbers

Submissions to ENA result in accession numbers. A set of rules describe the format of the accessions, and these are described below, alongside examples of how they look. These accessions can be used to identify each unique part of your submission.

Please note, not all accessions become available in the browser and not all can be used in publications. For information on which accessions can be described in publications, see the guidelines at the bottom of this page.

Understanding these accessions can give you some information about what they refer to, even before you find them in our browser. For example, in the case of studies, samples, experiments, runs and analyses, you can identify which INSDC partner accepted the original submission by looking at the first letter: ‘E’ for ENA, ‘D’ for DDBJ, or ‘S’ for NCBI.

Accession Type Accession Format Example
Projects PRJ(E|D|N)[A-Z][0-9]+ PRJEB12345
Studies (E|D|S)RP[0-9]{6,} ERP123456
BioSamples SAM(E|D|N)[A-Z]?[0-9]+ SAMEA123456
Samples (E|D|S)RS[0-9]{6,} ERS123456
Experiments (E|D|S)RX[0-9]{6,} ERX123456
Runs (E|D|S)RR[0-9]{6,} ERR123456
Analyses (E|D|S)RZ[0-9]{6,} ERZ123456
Assemblies GCA_[0-9]{9}.[0-9]+ GCA_123456789.1
Assembled/Annotated Sequences
(including contig, scaffold
and chromosome sequences
generated from an assembly
Protein Coding Sequences

How to cite your ENA study

In all cases, the top-level Project accession should be cited as well as a link to where the data can be found in the browser, for example:

“the data for this study have been deposited in the European Nucleotide Archive (ENA) at EMBL-EBI under accession number PRJEBxxxx (”

If there is a particular scenario where using the top level accession would not be suitable, for example, if you have multiple publications that reference individual components within a single ENA project (and therefore the project accession provides too much ambiguity), then the following accessions are also considered accessions that could be used for publication:

  • Assemblies
  • BioSamples (in the context of associated data)
  • Assembled/Annotated Sequences