Figure 1.

Phylogenetic tree of GH18 domains from 36 mammalian proteins. The phylogenetic trees presented in this paper were constructed with Mega version 3.1 software [86]. Minimum evolution, neighbor-joining, and maximum parsimony methods were used with Poisson correction for multiple amino acid substitution and with 1000 random bootstrap replicates. The figure shows the minimum evolution tree (the three methods produced very similar topologies). Alignment of the GH18 domain amino acid sequences used ClustalX (1.83) [84]. Gene symbols (or protein symbols where genes symbols are not available) and binomen species abbreviations of the form "Gsp" (Genus, species) are used. The GH18 proteins comprise three major phylogenetic groups, with the chitinase/chitolectin group forming four subgroups denoted I, II, III and IV (discussed in the text). The scale at the bottom left is in units of amino acid substitutions per site. Bootstrap values ≥ 95% are shown. The tree is rooted with the Serratia marcescens family GH18 chitinase A [GenBank:P07254].