The unveiling of the zebra finch genome also provides exciting insights into the evolution of avian and mammalian species. As detailed by the consortium authors, the genome lacks genes that encode milk, salivary and vomeronasal receptor proteins, similarly to what has been documented for the chicken, a non-vocal-learning avian species whose genome was uncovered 6 years ago. Curiously, similarly to chickens, zebra finches lack the synapsin I gene, which encodes a phosphoprotein involved in the regulation of neurotransmitter vesicle availability in pre-synaptic membranes. This finding suggests that the synaptic transmission machinery differs between mammalian and avian species, although it is not clear if such molecular changes translate into functional modifications at the systems level.