FASTA format is the standard input format for BLAST (developed by Altschul et al., 1990, at NCBI). FASTA format consists of a header line beginning with '>' (containing the sequence ID and description) followed by the nucleotide or amino acid sequence in subsequent lines. BLAST uses this query sequence to search databases (GenBank, UniProt, etc.) for similar sequences using a heuristic local alignment algorithm. GenBank, EMBL, and PIR are database formats, not the primary BLAST input format.