Figure 2: Phylogeny of CRK, CRKL, and Their Orthologs.
From: A pre-metazoan origin of the CRK gene family and co-opted signaling network
The maximum likelihood tree was built using RAxML program based on the nucleotide alignment of CRK/CRKL homologs shown in Supplementary Figure S6a. Vertebrate CRK and CRKL clades are colored blue or magenta, respectively. A bootstrap value is shown at the base of each clade. The scale bar indicates the rate of substitutions. Note that all invertebrate orthologs cannot be distinguished as either CRK or CRKL. Vertebrate crk, crkl and their invertebrate orthologs (CRK-CRKL ancestral; crka) form distinct clades consistent with their known phyla and subphyla indicated on left. The red line separates the metazoa and premetazoa. The diagram shown at the top right is a simplified structure based on three conserved SRC homology domains. Numbers below each domain indicate the percent identity of pairwise comparisons with human CRK, after all gaps are removed from the nucleotide alignment. YxxP indicates a motif of the internal SH2 binding site. The + or – symbols below YxxP indicates the presence or absence of this motif. The percent identity of M. brevicollis crka2 SH3c (asterisk) was much lower before removal of gaps (13%), compared with after gap removal (50%). In contrast, the percent identities of M. brevicollis crka1 SH3c was 44% before gap removal. Details of the alignment as well as additional phylogenetic trees are provided in Supplementary Figures S6 and S7.
