Biological Databases

The most important basis for applied bioinformatics is the collection of sequence data and its associated biological information. For example, with genome sequencing projects such data are generated daily in very large quantities worldwide. To use these data appropriately, a structured fi ling system of these data is necessary, yet the data should also be accessible to those interested. Annually, the journal Nucleic Acids Research [nar] dedicates an entire issue (fi rst issue in January) to all available biological databases, which are recorded in tabular form with the respective URLs. Furthermore, for a number of databases, original articles describe their functions. This database issue, which is freely accessible also on the WWW, is a good starting point for working with biological databases. Depending on the kind of data included, different categories of biological databases can be distinguished. Primary databases contain primary sequence information (nucleotide or protein) and accompanying annotation information regarding function, bibliographies, cross-references to other databases, etc. Secondary biological databases, however, summarize the results from analyses of primary protein sequence databases. The aim of these analyses is to derive common features for sequence classes, which in turn can be used for the classifi - cation of unknown sequences (annotation). In addition, all other databases that save biological or medical information, e.g., literature databases, are frequently classifi ed as secondary databases.