An identified Schmidtea MMP gene is related to Hydra MMP and to MMPs from insects and mammals. (A) All known MMPs from the fully genome sequenced ecdysozoan Drosophila melanogaster and humans (Deuterostomia) were aligned with the Schmidtea-MMP (AY068367) and the active site sequences are shown (MMP active site consensus sequence: HEXGHXXGXXHS). (B) A Bayesian protein tree was generated and we found that the Schmidtea-MMP grouped together with the MMP from H. vulgaris (AAD45804) nearest to MMP-1 from D. melanogaster. UniProt accession numbers for MMPs are: Drosophila1, Q9GTK3; Drosophila2, Q8MPP3; Human19, Q99542; Human28, Q9H239; Human11, P24347; Human21, Q8N119; Human17, Q9ULZ9; Human25, Q9NPA2; Human14, P50281; Human15, P51511; Human16, P51512; Human24, Q9Y5R2; Human20, O60882; Human12, P39900; Human13, P45452; Human1, P03956; Human8, P22894; Human3, P08254; Human10, P09238; Human7, P09237; Human26, Q9NRE1; Human23, O75900; Human2, P08253; Human9, P14780. Posterior probabilities are plotted at nodes. The scale bar represents the substitutions per site.