Phylogenetic trees based on alignments of periostin sequences. (A) The phylogenetic tree obtained from a protein sequence alignment of periostin from seven tetrapod species (Hs, Mm, Md, Oa, Gg, Ac, Xt) and 5 teleost species (Dr, Ga, Ol, Tr, Tn). Numbers at the branch points are bootstrap values. For the teleosts, both periostin loci were considered, except for Ol, where periostin from the second locus was not reconstructed.
The dendrogram accurately reproduces established taxonomic lineages (adapted from the NCBI Taxonomy Browser ) for the species in question as given on the right, with the minor exception of the branching order of Md and Oa. It clearly places the periostin duplication event at the base of the teleosts, with the same subtree structure replicated between the two loci.
(B) Phylogenetic trees based on tetrapod protein sequence alignments of periostin exons 1 - 15 (left) and 16 - 23 (right), scaled for identity of branch length units (see 0.02 marker), which are given at the branch points. The right dendrogram has generally longer branches, most profoundly for Xt, reflecting the increased rate of evolution of periostin's C-terminal region.