Bioinformatics Milestones
You've just cloned and sequenced a gene, but you don't know what it does. Now what do you do? In the absence of functional clues, it's hard to know where to start. One approach is to ask what other known sequences are similar to yours, thereby inferring function from homology.
Each weekday, some 200,000 or so researchers do just that, asking a server at the National Center for Biotechnology Information (NCBI) in Bethesda, Md., to compare their particular sequence against GenBank, a DNA database that, at the end of 2004, held more than 40 million sequences totaling 44.5 billion nucleotides. The NCBI devotes 158 two-processor computers to those queries, 75% of which return within 22 seconds.
The software these servers use, a sturdy 15-year-old program known as the Basic Local Alignment Search Tool, or BLAST, remains, for many, bioinformatics' "killer app." It wasn't the first DNA database search ...
