Phylogenetic tree of SEA domains in human, mouse, chicken and zebrafish. A neighbor-joining tree was obtained by ClustalW using 1000 bootstrap replicates. Bootstrap percentages above 50 are shown. The groups containing the Muc1, Muc13 and Muc16 mucins are shown with a shaded background. Animals represented are human (h), mouse (m), chicken (c) and zebrafish (z).