بلوسام

thumb|400px|The BLOSUM62 matrix, the amino acids have been grouped and coloured based on Margaret Dayhoff|Margaret Dayhoff's classification scheme. Positive and zero values have been highlighted. In bioinformatics, the BLOSUM (BLOcks SUbstitution Matrix) matrix is a substitution matrix used for sequence alignment of proteins. BLOSUM matrices are used to score alignments between evolutionarily divergent protein sequences. They are based on local alignments. BLOSUM matrices were first introduced in a paper by Steven Henikoff and Jorja Henikoff. They scanned the BLOCKS database for very conserved