Worthy of Note
BLAST-ing Off Into New Worlds of Biotechnology
Research
When it introduced BLAST, a sequence similarity search tool
designed to support analysis of nucleotide and protein databases, in
1990, NLM's National Center for Biotechnology Information could not
have imagined the effect that BLAST and its spinoffs would have on
genetics research.
Comparison, whether of morphological features or protein
sequences, lies at the heart of biology. And BLAST made it easier to
scan huge sequence databases for overt homologies (similarities) and
statistically evaluate the resulting matches.
With more than 8,700 citations to date, the paper describing the
original algorithm, published in 1990, has since become the most
heavily cited of the decade. This means that the methods outlined in
the article have been used to make many other discoveries.
Not all significant homologies are overt, however. Some of the
most interesting are subtle and do not rise to statistical
significance during a standard BLAST search. NCBI's Stephen
Altschul, PhD, the key figure in the creation of BLAST, has extended
BLAST and its statistical methodology to address the problem of
detecting weak but significant sequence similarities. With a small
group of NCBI researchers, he has developed Position- Specific
Iterated BLAST (PSI-BLAST), which searches sequence databases with a
profile constructed from BLAST alignments.
PSI-BLAST has proven to be a very powerful tool. And, among
scientific articles published in the past two years, the 1997 paper
describing PSI-BLAST has been the most heavily cited for the fourth
2-month interval in a row, with over 700 citations to date,
according to the Institute for Scientific Information. Because of
this strong citation record, PSI-BLAST and its development team were
featured in the April 12, 1999, issue of The Scientist.
Altschul's collaborators on PSI-BLAST were Alejandro Schäffer,
PhD, Tom Madden, PhD, and David Lipman, MD, Director of NCBI.
To learn more about BLAST and PSI-BLAST, visit the BLAST page at
www.ncbi.nlm.nih.gov/BLAST/
. An online tutorial is also available from that page; look for
"BLAST Course."
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