Scores for each position are obtained frequencies of substitutions in blocks of local alignments of protein sequences.;BLOSUM r:
:The matrix built from blocks with less than r% of similarity
:* E.g., BLOSUM62 is the matrix built using sequences with less than 62% similarity (sequences with >= 62% identity were clustered together).
:* Note: BLOSUM 62 is the default matrix for protein BLAST. Experimentation has shown that the BLOSUM-62 matrix is among the best for detecting most weak protein similarities.

Several sets of