Clustal X is a graphical interface for the ClustalW multiple sequence alignment - program. Sequences can be colored either by assigning a color to specific + program. Sequences can be coloured either by assigning a colour to specific residues, or on the basis of an alignment consensus. The residues in each - column are colored according to the consensus character assigned to that column. + column are coloured according to the consensus character assigned to that column. In this way, you can choose to highlight, for example, conserved hydrophylic or hydrophobic positions in the alignment.