Phylogenetic tree of vertebrate Argonaute rooted by closely related invertebrate homologues. The major vertebrate subgroups are: Argonaute 1/eukaryotic translation initiation factor 2C, 1 (Eif2c1) [Ago1], Argonaute 2/EIF2C2 [Ago2], Argonaute 3/EIF2C3 [Ago3] and Argonaute 4/EIF2C2 [Ago4]. Phylogenetic reconstruction method, species colour-coding and nodes labeling of significance are the same as Fig. 1. The multiple sequence alignment file is given in Additional file 3.