Extended Data Figure 6: Initial phylogenetic analysis of two GPCRs expressed in the PPE-derived neurons of Ciona intestinalis.

This broad survey tree, constructed according to maximum likelihood, shows the approximate placement of the two GPCRs of interest (boxed in blue) within the rhodopsin-class G-protein-coupled receptors. The numbered Ciona sequences and their receptor-type identifications in parentheses are from Kamesh et al.³⁷. All non-Ciona sequences were downloaded in bulk from http://pfam.xfam.org; they comprise the Pfam ‘seed’ alignment of seven-transmembrane receptors for the GPCRs. The rhodopsin subclass names are given to the right of each coloured group. The asterisk and double asterisk indicate the genes labelled RXFP3 and SOG/Chemokine-like, respectively, in Fig. 2e. We judge robust nodal support as bootstrap percentages >70 for minimum evolution (ME) and maximum likelihood (ML) and posterior probability percentages >95 for Bayesian inference (BI).