The Clustal series of programs are widely used in molecular biology for the multiple
alignment of both nucleic acid and protein sequences and for preparing phylogenetic
trees. The popularity of the programs depends on a number of factors, including not
only the accuracy of the results, but also the robustness, portability and user-friendliness
of the programs. New features include NEXUS and FASTA format output, printing range
numbers and faster tree calculation. Although, Clustal was originally developed to
run on a local computer, numerous Web servers have been set up, notably at the EBI
(European Bioinformatics Institute) (http://www.ebi.ac.uk/clustalw/).