Circle phylogenetic tree of 459 DHQases, constructed with Maximum Likelihood method with 1000 bootstrap replications. The salmon color range covers all species with type I DHQases, the light green range covers all species with type II DHQases. The codes for the 38 selected DHQases were assigned outside circles. For the outmost color ring, colored strips indicate the origins (at phylum levels) of the DHQases: Firmicutes is marked with red strips, Proteobacteria is green, Actinobacteria is yellow. All archaea including Thaumarchaeota,Crenarchaeota, and Euryarchaeota are showed in dark blue. Species from other phylum is left with no color strips. Capital letters A-G indicated7 big clades with bootstrap support values >70%.