What is BLAST and what is it used for?

BLAST (Basic Local Alignment Search Tool) is a sequence similarity search algorithm used to compare a query sequence against a database of sequences to find regions of similarity. It identifies homologous genes and proteins by finding local alignments with statistically significant similarity. Different BLAST programs exist: BLASTn (nucleotide vs nucleotide), BLASTp (protein vs protein), BLASTx (translated nucleotide vs protein), tBLASTn (protein vs translated nucleotide), and tBLASTx (translated vs translated). BLAST is essential for gene identification, functional annotation, and evolutionary studies.