Maximum-likelihood phylogenetic reconstruction of individual HYDA sequences (A) and a concatentation of HYDAEFG (B).

Bootstrap support values are indicated at each node. The root in the HYDA (NAR1, paralogs of HYDA) was pruned to conserve space. Given that NAR1 paralogs of HYDEFG do not exist, a different outgroup was chosen (i.e HYDAEFG from Bacteroides thetaiotaomicron) on the basis that the HYDA that it encodes, which branches basal to the eukaryote HYDA lineage.