Definition of BLAST

BLAST: Abbreviation for Basic Local Alignment Search Tool, a computer program that identifies homologous genes in different organisms (such as worms, the fruit fly, mice, and humans). Homologous genes are genes in different species that share similar structures and functions.

A surprisingly large proportion of the human genome shares homology with the genome of other organisms (such as the mouse, the fruit fly and even the round worm). BLAST helps by identifying the areas of homology. For example, there may be a gene in mice to do with liking (or not liking) to consume alcohol; using BLAST we can check the human genome in search of an homologous gene.