An overview of sequence similarity ("homology") searching.

Sequence similarity searching is an essential tool for molecular biologists. It is used to support inference of protein function and for phylogenetic analysis. Every searching procedure requires some understanding of the underlying principles, so at the very least the investigator's selection of parameters is correct. The principles underlying the most commonly used procedures are presented in this unit. The discussion is intentionally non-mathematical, but does contain references for those who desire a mathematical and statistical discussion of these procedures.