Aim to contain all protein or DNA sequence data - more is continually added as new discoveries are made. Include:
- Databases of Proteins: PIR, MIPS, SwissProt and TrEMBL
- Databases of DNA Sequences: EMBL, GenBank, DDBJ
Contain selected sequences which are compiled by scientists analysing the available Primary Databases. Usually contain sequences chosen for their similarities: for example, ProSite focuses on functional motifs.