On the basis of a bioinformatic approach, we suggest that in invertebrates many ligands interact with a single, ancestral and generalized receptor driving ligand evolution. In vertebrates, on the other hand, the occurrence of gene/genome duplications induced the shift to a ligand-directed evolution of receptors.
Evolution game: which came first, the receptor or the ligand? / Mandrioli, Mauro; Malagoli, Davide; Ottaviani, Enzo. - In: INVERTEBRATE SURVIVAL JOURNAL. - ISSN 1824-307X. - ELETTRONICO. - 4:(2007), pp. 51-54.