Phylogenetic analyses imply an ancient origin and multiple independent expansions of GiMAP/IAN-1 loci during evolution. The tree shown is the result of ML analyses, with the proportions of 100 ML bootstrap replicates and posterior probabilities (BI) shown for some of the major clades. Much of the tree is relatively poorly resolved, but (with the exception of Danio) most sequences for each species cluster together with high support, which is consistent with independent lineage-specific expansions. Additional files 5 and 6 respectively show the ML and BI trees with bootstrap/posterior probability support indicated for all nodes. Accession data for sequences used in the phylogenetic analyses and the alignment on which the analyses were based are shown as Additional files 7 and 8, respectively.