ncbi-blast+ - 2.12.0+ds-4+b1 main

The Basic Local Alignment Search Tool (BLAST) is the most widely
used sequence similarity tool. There are versions of BLAST that
compare protein queries to protein databases, nucleotide queries
to nucleotide databases, as well as versions that translate nucleotide
queries or databases in all six frames and compare to protein databases
or queries.
PSI-BLAST produces a position-specific-scoring-matrix (PSSM) starting
with a protein query, and then uses that PSSM to perform further searches.
It is also possible to compare a protein or nucleotide query to a
database of PSSM’s.
The NCBI supports a BLAST web page at blast.ncbi.nlm.nih.gov as well as
a network service.