Distance analysis of isomin and protostome cytoplasmic intermediate filament (IF) proteins. Reconstruction of the phylogenetic tree was performed using the neighbour-joining method of the PHYLIP software package. GenBank accession numbers, referred to the trmbl (tr) and swiss-prot (sp) databank, respectively, are followed by species names. Different phyla are represented by diverse colours. Note: molluscan IF proteins cluster into two groups, corresponding to neuronal and non neuronal IF proteins. Only cytoplasmic complete IF sequences from protostome species have been included in this analysis.