Songbirds, parrots, and humans are rare in the animal kingdom for their ability to hear communication and then repeat it with accurate syntax and pronunciation. Whales and elephants can do this trick, too, but they’re not very practical laboratory animals. Knowing what genetic tools are involved in the bird brain’s speech systems will help Erich Jarvis greatly to tease out each step of the process in humans. Eight of the twenty-eight papers published as a result of the gene-sequencing effort were devoted to vocal learning.
The most striking finding from these vocal-learning papers is that there is a consistent set of just over fifty genes in the brains of humans and vocal-learning birds that show higher or lower activity. It’s not the presence or absence of these genes that matters, but their activity, Jarvis explains. “You can find those same fifty genes in the genomes of all species, but they’re active at much higher or lower levels in the specialized song or speech brain regions of vocal-learning birds and humans. What this suggests to me is that when vocal learning evolves, there may be a limited way in which the brain circuits can evolve.”
Jarvis says the new phylogeny shows that vocal learning evolved two to four times in the birds, and each time, the problem was solved by a similar approach. These patterns are not found in the brains of non-vocal-learning birds, nor in non-human primates.