The BLAST Program (Basic Local Alignment Search Tool) is a
bioinformatics tool extremely used to align sequences from genomic,
transcriptomic and proteomic data. In the "OMICS" territory, it
constitutes one of the most used tools by a number of professionals
such as biologists, informaticians, molecular biologists, geneticists,
chemistry engineers and, obviously, by bioinformaticians. The program
aims to determine by heuristics DNA, RNA or proteic sequences that
reach a chosen similarity value e that, therefore, can be analyzed by
means of homology. The output from the various BLAST modules available
both via Web and local (StandAlone versions) can reveal whether the
sequences are evolutionarily related and may suggest biological
function that is shared through a process called Annotation Process.
This process consists in the determination of classes and identities
stablished in databases which are populated with previous known
function. Although BLAST, per se,
is not able to annotate data, it allows one to choose which database
will be used during a systematic search. Those interested in performing
an alignment with the BLAST algorithm always choose the database and
must format the database sequences before running the program (when
"StandAlone" versions are used). Therefore, it is also very important
to know - in the bioinformatics talk - "against who the input
sequence(s) is/are being BLASTed", that is, to know well the database
used in the BLAST alignment. The best way to use the program is through
the Internet by accessing the NCBI''s site
(http://www.ncbi.nlm.nih.gov). NCBI stands for National Center for
Biotechnology Information. After accessing the web site, one should
look for an link right above at the header''s bar. And enjoy the trip.
Written and translated by Eduardo Capanema Xavier