Language is a trait that sets humans apart from all other species, and researchers are interested in understanding how, when, and why complex language evolved in hominins. This doctoral dissertation project will use a non-human model to understand neuro-genetic changes that correlate with increased social learning and flexibility of vocal behavior. These data will be compared with human and chimpanzee genomic data to identify potential shared evolutionary mechanisms in the evolution of birdsong and human language. By illuminating the molecular mechanisms of auditory perception that support learning of a more flexible vocal behavior in the model system, the research may shed light on our understanding of normal functionality and disorders of human speech. The project will also include public and K-12 science outreach activities in the San Francisco Bay Area.
This project will empirically investigate the genetic and evolutionary processes that correlate with increased flexibility of vocal learning and behavior in the White-Backed Munia (WBM)/Bengalese Finch (BF) songbird system. The researchers will then investigate potentially analogous genetic and functional pathways involved in the evolution of flexible human vocal learning capacities with respect to those of other primates. Specific aims of the project include: (i) an investigation of the evolutionary forces underlying the changes in vocal behavior in BF relative to WBM utilizing whole-genome sequencing of individuals within the two bird strains and subsequent scans for signatures of positive or relaxed selection, thus allowing identification of candidate genes modified in this transition; (ii) an analysis of genetically regulated differences in neurological function correlated with differences in the flexibility of adult vocal production between BF and WBM, by comparing measures of gene expression for whole transcriptomes from main birdsong-related brain areas of BF and WBM adult males exposed to unfamiliar conspecific song; and (iii) a comparison of the birdsong data to neuroanatomical and genomic data provided by studies of human divergence from closely related primates (e.g. chimpanzee) to identify possible evolutionary parallelisms.
