NCBI Sequence Read Archive (SRA)
The Sequence Read Archive (SRA) is designed specifically meet the challenges presented by massively parallel sequencing technologies.
  • Provide a central repository for next generation sequencing data.
  • Provide links to other resources referencing or using this data.
  • Provide users with retrieval based on ancillary information and sequence comparison.
  • Track studies and experiments (project metadata).
  • Allow flexible submission and retrieval of ancillary data.
  • Improve database efficiency through normalization of data structures.
  • Separate submission from content.
  • Establish basis for user-interactive submission and retrieval.

SRA Data Accessions


SRA - SRA submission accession. SRP - SRA study accession. SRX - SRA experiments accession. SRR - SRA run accession. SRS - SRA sample accession. SRZ - SRA analysis accession.


ERA - ERA submission accession ERP - ERA study accession ERX - ERA experiment accession ERR - ERA run accession ERS - ERA sample accession ERZ - ERA analysis accession


DRA - DRA submission accession DRP - DRA study accession DRX - DRA experiment accession DRR - DRA run accession DRS - DRA sample accession DRZ - DRA analysis accession

Link: SRA Knowledge Base.
The Gene Expression Omnibus (GEO) is a public repository that archives and freely distributes submitted microarray, next-generation sequencing, and other forms of high-throughput functional genomic data.
GSE: A GEO Series (GSExxx) is an original
     submitter-supplied record that summarizes
     a study.
GDS: Reassembled and curated GEO Datasets.
Both Series and DataSets are searchable using the GEO DataSets interface, but only DataSets form the basis of GEO's advanced data display and analysis tools including gene expression profile charts and DataSet clusters, see the Data organization document for more information. Not all submitted data are suitable for DataSet assembly and we are experiencing a backlog in DataSet creation, so not all Series have a corresponding DataSet record(s). Raw sequence data have been uploaded to NCBI Seq- uence Read Archive (SRA) database, and linked from Sample and Series records, available in 'sra' format.
GSM: GEO sample unique and stable accession number. GDS: Reassembled into GEO Dataset records by GEO staff. GPL: GEO Platform accession.
Link: GEO FAQ.
SAMN: Biosample accession number.