SeaView is a graphical multiple sequence alignment editor developped by Manolo Gouy.

SeaView is able to read and write various alignment formats (NEXUS, MSF, CLUSTAL, FASTA, PHYLIP, MASE). It allows to manually edit the alignment, and also to run DOT-PLOT or CLUSTALW programs to locally improve the alignment.

SeaView can be used as a standalone application or as a helper application when using the World Wide Web. In this case, prospective users must configure their WWW browser in a way to make it able to recognize the MIME-type associated to the data read by SeaView: chemical/mase.

References:
Galtier, N., Gouy, M. and Gautier, C. (1996) SeaView and Phylo_win, two graphic tools for sequence alignment and molecular phylogeny. Comput. Applic. Biosci., 12, 543-548.[Entrez]