Researchers at Oregon Health & Science University are part of an international research effort to decode the genome of the zebra finch, a songbird species found in Australia. The zebra finch has been studied in labs around the world because it shares many complex behavioral traits with humans. At OHSU, songbirds are studied because the process in which they learn their songs is very similar to the ways that humans learn spoken language. The research is published in the April 1 online edition of the journal Nature.
"The zebra finch is one of a few known animal species, other than humans, in which juveniles learn their vocalizations from adult animals, typically the father," explained Claudio Mello, Ph.D., an associate professor of behavioral neuroscience in the OHSU School of Medicine. "In our lab, we have mapped the brain centers involved in hearing and learning in the zebra finch and find that there are many similarities with humans."
By studying a more experimentally tractable system in birds, researchers can learn much about how humans learn speech and language and the various problems that can limit or impede these skills. For example, traumatic injury, stroke and autism often lead to speech and language problems. In addition, it is hoped that speech difficulties such as stuttering can be better understood through the use of animal-based studies combined with human research.
The zebra finch genome is only the second bird genome to be decoded; the first was the chicken. Since the chicken and zebra finch lineages diverged nearly 100 million years ago, this research provides important insights into some major differences in evolution of bird genomes. However, the differences that are of the greatest interest to researchers at OHSU pertain to brain-based vocal learning abilities. While chickens vocalize through "clucks," they do not have the same genetically based brain structures to communicate through vocal learning that zebra finches do.
At OHSU, the Mello lab has been playing a central role in identifying gene regulatory mechanisms associated with song learning. The lab recently was awarded a grant from the National Institute of General Medical Sciences to generate a molecular atlas of the zebra finch brain by mapping the expression of genes of physiological and comparative interest, with a focus on vocal brain centers. In conjunction with the genome, this resource is expected to shed light on the genetic specializations related to speech and language function and impairments, as well as on important properties of the song system such as sensitivity to sex steroids and extended neurogenesis throughout adulthood.
More than 20 institutions, including OHSU, took part in the sequencing of the zebra finch genome. The project was led by the Washington University School of Medicine in St. Louis. The research was funded by the National Human Genome Research Institute, a component of the National Institutes of Health.
Oregon Health & Science University is the state's only health and research university and Oregon's only academic health center. OHSU is Portland's largest employer and the fourth largest in Oregon (excluding government). OHSU's size contributes to its ability to provide many services and community support activities not found anywhere else in the state. It serves patients from every corner of the state, and is a conduit for learning for more than 3,400 students and trainees. OHSU is the source of more than 200 community outreach programs that bring health and education services to every county in the state.