 Type I metacaspases are characterized by an amino-terminal proline or glutamine rich LSD zinc finger-like domain.This class can almost exclusively be found in plants, with one recent exception where both type I and type II metacaspases were found in the genome of "Monosiga brevicollis" (Choanoflagellate), possibly as a result of an unusual horizontal gene transfer between two eukaryotes.Type II has a wider phylogenetic distribution among all eukaryotes except those where paracaspases have been found (animals and slime mold).