Fig. 4. Phylogenetic analysis of AmphiTrk versus vertebrate Trk receptors and invertebrate Trk-related peptide sequences. (A) Phylogenetic tree generated with full-length sequences, (B) with isolated extracellular domains or (C) with tyrosine kinase domains only. In all cases, cladograms were calculated by the neighbour-joining method and bootstrap percentages over 1000 replicas are shown for every branch. Human and mouse ROR1 tyrosine kinase domains were used as outgroups in C.