Sequence logos are a graphical way for displaying patterns in a set of multiply aligned sequences. In each position of the alignment the residues (nucleotide bases or amino acids) are stacked one on top of another. The program receives an aligned set of sequences and creates a 'sequence logo'. The height of each residue is made proportional to its frequency, and the most common ones are on the top of the positions. The total height of each position is adjusted to signify the information content of the residues at that position. Sequence logos enable one to graphically display the consensus sequence (as the top letter in each stack of letters), the relative frequency of residues and the information content (precisely measured) of every position in the alignment. The logo displays both significant residues and subtle sequence patterns. The color, size, and style of the residues and texts can be be controlled as well as other parameters for the logo. The logo can be printed on any postscript printer (such as the MacIntosh printers) and viewed by the ghostscript program (for ghostscript you need to be able to open another window on the screen). References - Schneider T.D. and Stephens R.M. "Sequence logos: a new way to display consensus sequences. Nucleic Acids Res., 18(20):6097-6100, 1990. Stephens R.M. and Schneider T.D., "Features of spliceosome evolution and function inferred from an analysis of the information at human splice sites." J. Mol. Biol., 228(4):1124-1136, 1992. Papp P.P., Chattoraj D.K. and Schneider T.D. "Information Analysis of Sequences that Bind the Replication Initiator {RepA}", J. Mol. Biol., 233(2):219-230, 1993. Comment - See cover of issue (JMB, volume 233 number 2).