Review Article
Coevolution of Mucosal Immunoglobulins and the Polymeric Immunoglobulin Receptor: Evidence That the Commensal Microbiota Provided the Driving Force
Figure 5
Coevolution of mucosal Igs and pIgR. Simplified neighbor-joining phylogenetic trees of vertebrate (a) Ig and (b) pIgR protein sequences, with human IgA1 and pIgR denoted as outgroups. Horizontal distances are proportional to the degree of divergence following a multiple alignment of amino acid sequences. Numbers at nodes denote bootstrap support for each bifurcation after 100 replications. Accession numbers for mucosal Ig sequences: human (Homo sapiens) IgA1, J00220; IgA2 (allotype m1), J00221; gorilla (Gorilla gorilla) IgA1, X53703; IgA2, X53707; chimpanzee (Pan troglodytes) IgA1, X53702; IgA2, X53706; gibbon (Hylobates lar) IgA1, X53708; IgA2, X53709; Bornean orangutan (Pongo pygmaeus) IgA, X53704; baboon (Papio anubis) IgA, DQ868435; rhesus macaque (Macaca mulatta) AY039245; pig (Sus scrofa) IgA, U12594; cattle (Bos taurus) IgA, AF109167; dog (Canis lupus familiaris) IgA, L36871; horse (Equus caballus) IgA, AY247966; mouse (Mus musculus) IgA, D11468; rabbit (Oryctolagus cuniculus) IgA1, X51647; brushtail possum (Trichosurus vulpecula) IgA, AF027382; duck-billed platypus (Ornithorhynchus anatinus) IgA1, AY055778; IgA2, AY055779; chicken (Gallus gallus) IgA, AAB22614.2; leopard gecko (Eublepharis macularius) Ig“A” (so designated because of its uncertain phylogeny with homology to both IgA and IgY), ABG72684.1; African clawed frog (Xenopus laevis) IgX, S03186; rainbow trout (Oncorhynchus mykiss) IgT, AAW66981.1. Accession numbers for pIgR sequences, with species that vary from those used for the mucosal Ig alignment in panel A noted in parentheses: human, NM_002644; chimpanzee, XM_003308710; gorilla, XM_004028295; gibbon, XM_003272974; Sumatran orangutan (Pongo abelii), NM_001131626; baboon, XM_003893189; rhesus macaque, XM_001083307; pig, NM_214159; cattle, NM_174143; dog, XM_537133; horse, XM_001492298; mouse, NM_011082; rabbit, NM_001171045; brushtail possum, AF091137; duck-billed platypus, XM_001508602; chicken, NM_001044644; green anole (Anolis carolinensis), XM_003224013; African clawed frog, EF079076; rainbow trout, FJ940682.
