Primary Databases are repository of raw sequenced and annotated data generated experimentally by scientists or researchers. These databases can be accessed freely. They have their own set of submission and retrieval tools, but they exchange data daily basis to make same set of sequences available.
GenBank: This database is an open access and annotated collection of nucleotide sequences. The database also contains their protein translations including mRNA sequences with coding regions, segments of genomic DNA with a single gene or multiple genes and ribosomal RNA gene clusters. GenBank is maintained by the National Centre for Biotechnology Information (NCBI) as part of the International collaboration with EMBL and DDBJ. Individual laboratory can submit sequence data or large scale sequencing centre can submit bulk submission directly to the GenBank by using Banklt or Sequin.
DDBJ (DNA Data Bank of Japan): Like Genbank it is also a kind of nucleotide sequence data bank that receives nucleotide sequence from researchers. DDBJ is open for all but it collects sequence data mainly from Japanese researchers. DDBJ began data bank activities in 1986 at National Institute of Genetics (NIG). Currently, DDBJ is in operation at NIG in Mishima, Japan. Information of DDBJ can be accessed through the server http://www.ddbj.nig.ac.jp.
EMBL (European Molecular Biology Laboratory): EMBL was established in 1980 at the EMBL in Heidelberg, Germany. It was the world's first nucleotide sequence database. The aceess of EMBL is free. It performs basic research in computational biology along with an extensive user training programme for the researchers. EMBL-EBI stores data on DNA and RNA, gene expression, protein fs), structure, systems, chemical biology, ontologies etc. EMBL-EBI can be accessed through the server http://www.ebi.ac.uk.
Swiss-Prot: A curated protein sequence database that provides detailed information about protein functions.
Composite database: The biological databases that deals with data of different primary databases for nucleotide sequence, protein sequence, protein structure etc.
Examples of some composite databases are
1. nrdb (nonredundant database) combines and stores sequences from GenBank (CDS translations), PDB, Swiss-Prot, PIR, and PRF. we can access it from Non-redundant databases (pubmlst.org)
2. INSD (International Nucleotide Sequence Database) stores nucleotide sequences of EMBL, GenBank, and DDBJ. For More information visit (insdc.org)
3. UniProt (universal protein sequence database) is a collection of protein sequences from PIR-PSD, Swiss-Prot and TrEMBL. We can access it from UniProt
You can also read Nucleic Acid Databases , Biological Databases , Primary, Secondary and Composite Databases, Nucleic Acid Databases
