BLAST Basic Local Alignment Search Tool is a sequence homology search tool. Given a probe sequence (nucleotide or protein), BLAST compares it to a sequence database and picks out sequences with significant similarity to the probe sequence.

Below is a list of prerequisites for using BLAST:

• GCC Compiler

To load BLAST type the following:

$ module load gcc blast

NCBI BLAST includes e.g. the following programs

• blastall: normal BLAST searches (blastp, blastn, blastx, tblastn, or tblastx)

For help type blastall -

• blastclust: clusters protein or DNA sequences based on pairwise matches found using the BLAST or MegaBLAST algorithm.
• blastpgp: performs gapped blastp searches and can be used to perform iterative PSI-BLAST and PHI-BLAST searches.
• bl2seq: performs a comparison between two sequences using the blast algorithm.
• megablast: uses the greedy algorithm of Webb Miller et al. for nucleotide sequence alignment search and concatenates many queries to save time spent on scanning the database.