DDBJ Center is officially certified to collect nucleotide sequences from researchers and to issue the internationally recognized accession number to data submitters. The accession number issued for each sequence data is unique on the database and internationally recognized to guarantee the submitter the property of the submitted and published data. Since DDBJ Center exchanges the released data with ENA/EBI and NCBI on a daily basis, the three data centers share virtually the same data at any given time. The virtually unified database is called INSD; International Nucleotide Sequence Database.