Read data including bases, base qualities and alignments can be submitted in several different formats ... more information.
The metadata model consists of the following objects each controlled by a XML Schema. The latest schema versions are available through FTP from ftp://ftp.sra.ebi.ac.uk/meta/xsd/sra_1_5 and are kept under version control in https://github.com/enasequence/schema.
|SRA.submission.xsd||A submission action to be performed by the archive.|
|SRA.sample.xsd||Detailed information about the sequenced sample. Samples can be used in any number of experiments.|
|SRA.study.xsd||A study groups together experiments or analyses for public data release purposes.|
|SRA.experiment.xsd||An experiment contains instrument and library preparation information and groups together one or more runs.|
A run contains sequencing reads submitted in data files (e.g. BAM or CRAM).
|SRA.analysis.xsd||An analysis contains secondary analysis results. for example: read alignments (BAM or CRAM), sequence variations (VCF) of sequence annotations (TAB).|
|SRA.common.xsd||Common types used in other SRA XML schemas.|
|EGA.dac.xsd||An European Genome-phenome Archive (EGA) data access committee (DAC). Required for authorized access submissions.|
|EGA.policy.xsd||An European Genome-phenome Archive (EGA) data access policy. Required for authorized access submissions.|
|EGA.dataset.xsd||An European Genome-phenome Archive (EGA) data set. Required for authorized access submissions.|
Each metadata object is assigned a unique accession number by the archive. The accession numbers can be used to retrieve data and metadata using the EB-Eye search available at the top of all EBI web pages or using the free text search available on the ENA home page. The metadata is then retrieved and displayed through the ENA Browser as in the examples in the above table.
Accession numbers assocaited with read data assigned by EBI start with 'ER' and accession numbers assigned by NCBI and DDBJ start with 'SR' and 'DR', respectively. The third letter of the accession number indicates the type of the metadata object. EGA accession numbers start with 'EGA' with the fourth letter indicating the type of the metadata object.
The accession numbers have a fixed number of digits after the letters: six for ENA and eleven for EGA.
|Metadata object||Accession prefix||Number of digits||Example|
|Submission||ERA, SRA, DRA||6||ERA000092|
|Sample||ERS, SRS, DRS||6||ERS000081|
|Study||ERP, SRP, DRP||6||ERP000016|
|Experiment||ERX, SRX, DRX||6||ERX000398|
|Run||ERR, SRR, DRR||6||ERR003990|
|Analysis||ERZ, SRZ, DRZ||6||ERZ000001|
|EGA Data Set||EGAD||11||EGAD00001000001|
Once made public, data submitted to ENA are available for download using ftp and Aspara. Detailed data download instructions are available here including details of the archive generated fastq files and their organisation.