The genome contains code for proteins that guide brain development.

Genomes contain codes for proteins that guide brain development, such as molecules that guide the pathways of developing axons, shaping distinct circuits. Birds’ brains have so-called “song circuits” that are active when the birds sing. These circuits also respond to the song of a bird’s own species more strongly than to other species’ songs. So the theory is that a bird’s genes guide development of brain circuits that relate to singing and the ability to learn songs.