BLAST (Basic Local Alignment Search Tool)
BLAST is a bioinformatics tool developed by the National Center for Biotechnology Information (NCBI) in 1989. It is used to compare nucleotide (DNA/RNA) or protein sequences against databases of known sequences. The tool helps in identifying similarities between sequences, which can be crucial for species identification, gene discovery and evolutionary studies.
Key Features of BLAST:
1. Query Sequence: The sequence of interest that is compared to a database.
2. Subject Sequence: The sequences in the database that are compared to the query sequence.
3. E-value: This indicates the likelihood that a match occurs by chance. A lower E-value represents a more significant match.
4. Similarity Score: Measures how closely the query sequence matches the subject sequence.
5. Max Identity: Shows the percentage similarity between the query and subject sequences.
Types of BLAST
- Nucleotide BLAST (blastn): For comparing DNA sequences.
- Protein BLAST (blastp): For comparing protein sequences.
- Translated BLAST (blastx, tblastn): For comparing nucleotide sequences with protein databases, or vice versa.
BLAST is widely used in research for identifying genes, finding evolutionary relationships, and detecting functional similarities between sequences. It provides fast and accurate results, making it one of the most essential tools in bioinformatics.
You can also read Nucleic Acid Databases , Biological Databases , Primary, Secondary and Composite Databases, Nucleic Acid Databases
