Archiving molecular phylogenetic alignments as NEXUS Systematic Biology

Many researchers working on the phyloge-netic analysis of nucleotide or amino acid se-quences ® nd it necessary, at some time, to build uponpriorwork.When this involves importing an alignment (and masks) that have been des-cribed and sometimes illustrated in a published paper but for which the sequences have not been deposited in a public database, there may be no alternative but to painstakingly retype the data, with all the possibilities that this o ers for error. More commonly, the un-aligned sequences may be available from a se-quence database, but the awkward task of man-ual alignment reconstruction remains. Most conveniently, alignments may be available as computer ® les (1) on disk, by application to the corresponding author, (2) from an ftp o