To help determine the genetic basis and evolution of this vocal learning, an international team of scientists – led by Dr. Wesley Warren, Research Associate Professor in the Department of Genetics at Washington University – has decoded the genome of the Australian zebra finch songbird. This is only the second bird to have its complete genome sequenced. The first was the chicken, which was also completed at The Genome Institute.
An analysis of the genome, published in the journal Nature, suggests a large part of the bird’s DNA is actively turned on or off by hearing and singing songs. The simple melodies last only a few seconds but are rooted in tremendous genetic complexity.
The research provides insights to help scientists understand how humans learn language. Many of the same genes involved in the bird’s ability to learn songs are also involved in human language learning. The work also sets the stage for future studies that could help identify the genetic and molecular origins of speech disorders, such as those related to autism, stroke, stuttering and Parkinson’s disease.
“Now we can look deep into the genome, not just at the genes involved in vocal learning, but at the complex ways in which they are regulated,” says senior author Dr. Richard Wilson, The Genome Institute’s Director. “There are layers and layers of complexity that we’re just beginning to see. This information provides clues to how vocal learning occurs at the most basic molecular level in birds and in people.”
Among songbirds, singing is almost exclusively a male activity: Males serenade females with love songs to attract a mate. As babies, they learn to sing by listening to their fathers. At first, a young bird “babbles,” but with practice learns to closely imitate his father’s song. Once the bird has mastered the family song, he will sing it for the rest of his life and pass it on to the next generation. For a sample of the bird’s song, click here. (Audio courtesy of David F. Clayton.)
Aside from humans and songbirds, other animals known to communicate by vocal learning include bats, whales, elephants, hummingbirds and parrots. Because zebra finches learn to sing in a predictable way and many of their genes are conserved in humans, they are an important model for understanding vocal learning in humans.
The zebra finch has also been a useful model for studying brain growth – in particular, the growth of new nerve cells, a process called “neurogenesis.” Prior to these kinds of studies, scientists thought that adult mammals didn’t generate new nerve cells after a certain age. But this idea was overturned once the process was discovered in the zebra finch.
“Sequencing the genome of the zebra finch has led to a discovery about how new neurons are continuously being born throughout life in songbirds,” says Dr. David Clayton, Professor of Cell and Developmental Biology at the University of Illinois. He adds: “We have learned that new neurons are created throughout the life of the human brain as well. The fact that the brain has more plasticity, versus being a fixed object, gives us further insight into how humans learn.”
For more information about the zebra finch, please visit our zebra finch genome web page or this video.
Funding for sequencing and characterization of the zebra finch genome was provided by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health (NIH).