In bioinformatics, BLAST (Basic Local Alignment Search Tool) is an algorithm for comparing primary biological sequence information, such as the amino-acid sequences of different proteins or the nucleotides of DNA sequences. A BLAST search enables a researcher to compare a query sequence with a library or database of sequences, and identify library sequences that resemble the query sequence above a certain threshold. Different types of BLASTs are available according to the query sequences. For example, following the discovery of a previously unknown gene in the mouse, a scientist will typically perform a BLAST search of the human genome to see if humans carry a similar gene; BLAST will identify sequences in the human genome that resemble the mouse gene based on similarity of sequence.
Altschul,S.F., Gish,W., Miller,W., Myers,E.W. and Lipman,D.J. (1990) Basic local alignment search tool. J. Mol. Biol., 215, 403–410.
| Query Type | Database Type | BLAST Program |
|---|---|---|
| Nucleotide | Nucleotide | : Search a nucleotide database using a nucleotide query. |
| Protein | : Search protein database using a translated nucleotide query. | |
| Protein | Nucleotide | : Search translated nucleotide database using a protein query. |
| Protein | : Search protein database using a protein query. |