Fig. 5

Phylogenetic tree to illustrate the evolution of Tektin-2 in bilaterian species. This phylogenetic analysis includes the Tektin-2 sequences identified in bilaterian species. The 23 spiralians include six mollusks (Ac, Bg, Ob, Lg, Cg, Pf), twelve platyhelminthes (Cs, Ov, Sch, Scm, Scj, Eg, Emu, Taa, Tas. Hmi, Sme, and Mli), three annelids (Pd, Ct, Hr), one brachiopod (La), and one orthonectid (Il). The ecdysozoans include many insects, two chelicerates (Pt, Smi), one myriapod (Sma), one tardigrade (Hd), and one priapulid (Pc). The invertebrate deuterostomes are represented by one echinoderm (Sp), one hemichordate (Sk), one cephalochordate (Bf), and one urochordate (Ci). The vertebrate deuterostomes are represented by three teleost fishes (Dr, Tr, and Ch), one holostei fish (Lo), one chondrichthyes (Cm), one sarcopterygian fish (Lc), three amphibians (Xl, Amb, Nvi), one reptile (Cpb), two avians (Ap, Gg), and three mammal species (Oa, Mm, Hs). In addition, the entire Tektin complement for an annelid (Pd) and human (Hs) was included as well as two choanoflagellate (Sr, Mo) sequences as outgroups. Both Bayesian and Maximum Likelihood analyses were performed using Mr. Bayes and RAxML, respectively. The Bayesian tree topology is shown. Node support is shown for non-terminal nodes. Posterior probability values from Mr. Bayes and bootstrap values from RAxML are shown above or below each node, respectively. Diamonds indicate support less than 80%. “X” under a node indicates that this node was not recovered in the RAxML maximum likelihood tree. The large colored boxes group Tektin-2 sequences of the three major bilaterian branches, the spiralians (green), the ecdysozoans (blue), and the deuterostomes (orange). The smaller colored boxes within ecdysozoans and spiralians highlight Tektin-2 gene duplications at the base of insect lepidopterans (light purple), and one duplication in the Platyhelminthes lineage including the planarian (Sme) and the parasitic trematodes and cestodes, but excluding the flatworm (Mli) (dark green), respectively. Note that tektin-2 exists as a single copy gene in most extant species with only two additional duplicates observed in the leech (Hr) and louse (Phc). Species abbreviations and accession numbers for each sequence are provided in Additional file 5