Amino acid sequences of the first half of MSEL- and VLDV-neurophysins from goose and chicken have been determined. Identical substitutions in positions 17, 18, 35, 36 and 41 of both neurophysins of a given species when compared with their mammalian counterparts suggest a gene conversion between vasotocin—MSEL-neurophysin and mesotocin—VLDV-neurophysin genes. This event, which has already been observed for three mammalian species, seems recurrent and would link the evolution of the two neurohypophysial hormone precursors.
Key Words mesotocin precursor - vasotocin precursor - avian neurophysins - gene conversion - neurophysin evolutionary linkage