Exploring an SRA entry
Overview of an SRA entry
The SRA (Sequence Read Archive) provides access to unassembled data (Figure 41). Accession numbers starting with 'ER' are assigned by EBI, while those starting 'SR' are assigned by NCBI and 'DR' by DDBJ. In other words, the original database the sequence was submitted to is identifiable by these two letter codes. This is important, because with SRA sequences submitted to EBI (ER entries) you can access both the original sequence as submitted by the author as well as normalized sequence data as 'Fastq Files'. By contrast, when using ENA to view SRA sequences submitted to NCBI (SR entries) or DDBJ (DR entries), you can only view the 'Fastq Files'.
Figure 41. SRA entry ERP000001.
SRA entry - Navigation tab
The Navigation tab allows you to explore all the Sequence Read Archive data associated with an entry. In this way you can browse SRA data by sample, experiment or run, and even see the original submission data (Figure 42).
Figure 42. SRA entry ERP000001 showing the Navigation tab.
SRA entry - References
Literature references relating to the SRA sequence are provided under the References tab (Figure 43). Cited literature should be considered as a pointer to scientific information and not a credit for the elucidation of the sequence.
Figure 43. SRA entry ERP000001 showing the References tab.