Phylogenetic trees and domain composition of Class I and Class II SDG proteins. Maximum likelihood phylogenetic trees of Class I (A) and Class II (B) SDG predicted proteins from Arabidopsis thaliana (At) and Solanum lycopersicon (Sl). Bootstrap values higher than 50% are shown. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. Two EZD, SANT (SM00717), CXC (PF03638), and SET (PF00856) are conserved domains of Class I. N-terminal AWS (SM00570), SET and Post-SET (SM00508) are conserved domains of Class II. The PHD domain (PF00628) and CW domain (SM00605) are also found in Class II proteins.