Fig. 2

Unrooted bootstrap consensus phylogenetic tree. iGluR protein sequences for six deuterostomes and nine protostomes with iGluR information available were aligned using MUSCLE in MEGA7 and the tree was constructed using maximum likelihood and 1000 bootstrap replicates. iGluR subtypes are indicated by different colors. Numbers indicate bootstrap support and are displayed for boostrap values >0.6. The scale bar represents 0.4 substitutions per site. All species contain homologs for Grin1 and Grin2 subunits. An ancestral AMPAR and kainate receptor gene was present in the common bilaterian ancestor, but in the case of the kainate receptor, the monophyly is only weakly supported by bootstrap values