Figure 6

Coevolution of carcinoembryonic antigen related cell adhesion molecule (CEACAM)1-like members with immunoreceptor tyrosine-based inhibition motif (ITIM) and immunoreceptor tyrosine-based activation motif (ITAM)-like signalling motifs. The phylogeny of CEACAM1-like CEA family members from opossum (A), cattle (B), dogs (C) and humans (D) was reconstructed based on the amino acid sequences differences of mature N domains (minus leader signal peptide sequence) using the neighbour-joining method. The statistical support for each node is expressed as bootstrap values. Genes containing ITIM/immunoreceptor tyrosine-based switch motif encoding exons are marked with red boxes, such with ITAM and ITAM-like motif-encoding exons green and blue, respectively. Note, genes with ITIM or ITAM/ITAM-like signalling motif exons are either the closest relatives (B, C) or belong to the same subgroup of closely related members (A, D). Both opossum and humans contain a group of highly similar genes which code for secreted (human pregnancy-specific glycoproteins) or apparently secreted proteins. Bars below the phylogenetic trees indicate the scale for the number of substitutions per site.a, b, pseudogene