The evolution of ADAM gene family in eukaryotes

The ADAM (A Disintegrin And Metalloprotease) gene family encodes proteins with adhesion and proteolytic functions. ADAM proteins are associated with diseases like cancers. Twenty ADAM genes have been identified in humans. However, little is known about the evolution of the family. We analyzed the repertoire of ADAM genes in a vast number of eukaryotic genomes to clarify the main gene copy number expansions. For the first time, we provide compelling evidence that early-branching green algae (Mamiellophyceae) have ADAM genes, suggesting that they originated in the last common ancestor of eukaryotes, before the split of plants, fungi and animals. The ADAM family expanded in early metazoans, with the most significative gene expansion happening during the first steps of vertebrate evolution. We concluded that most of mammal ADAM diversity can be explained by gene duplications in early bone fish. Our data suggest that ADAM genes were lost early in green plant evolution. •ADAM gene family likely originated in the last common ancestor of eukaryotes and expanded specifically in vertebrates.•ADAM genes were likely lost in the early stages of evolution of the plant-lineage.•For the first time ADAMs genes were detect in a specific group of green algae.•The expanded ADAM repertoire in vertebrates is mostly explained by early gene duplications in their last common ancestor.•Vertebrate-exclusive ADAMs emerged associated with the evolution of more complex nervous system and fertilization mechanisms.