 The simplest method of template identification relies on serial pairwise sequence alignments aided by database search techniques such as FASTA and BLAST.More sensitive methods based on multiple sequence alignment – of which PSI-BLAST is the most common example – iteratively update their position-specific scoring matrix to successively identify more distantly related homologs.This family of methods has been shown to produce a larger number of potential templates and to identify better templates for sequences that have only distant relationships to any solved structure.