Phyletic distribution of the eukaryotic class 4 HDACs. Most of the species in which we sought class 4 HDACs are shown, together with our current view of their phylogenetic relationships . The nomenclature used for the phylogenetic groups is according to Simpson and Roger  and the NCBI website. In each case in which the genome of a species has been fully sequenced, we indicate the presence or absence of a "eukaryotic group" or "mixed group" class 4 HDAC. The # symbol denotes species for which only EST data are available. In these cases, our failure to find a class 4 HDAC of one type of the other does not mean that none exists. In the case of the fungi, we searched against the genomic data of all species available on the NCBI website and failed to find a class 4 HDAC in any of them. 'Phytophthora sp' are Phytophthora sojae + Phytophthora ramorum; 'Plasmodium sp' are Plasmodium berghei + Plasmodium chabaudi + Plasmodium vivax + Plasmodium yoelii yoelii; 'Trypanosoma sp' are Trypanosma cruzi + Trypanosma brucei.