Species-specific roles of Sox10 in the neural crest gene regulatory network Avila, AC and Rogers, CD 1California State University, Northridge; 2University of California, Davis alexis.avila.141@my.csun.edu, crdrogers@ucdavis.edu Neural crest (NC) cells are embryonic stem cells that give rise to craniofacial bone, pigment cells, and the peripheral nervous system. Understanding the molecular mechanisms that regulate the formation of NC cell development is crucial to identify causes for abnormal vertebrate development. Several transcription factors function as mediators of NC specification and migration, including Sox10, Sox9, and Pax7. I characterized expression of multiple NC transcription factors in chicken and identified that while the spatiotemporal expression of the factors is conserved, the NC protein function may not be. Gain and loss of function studies determined that overexpression of chicken SOX10 is sufficient to induce ectopic expression of SOX9, but not PAX7 in chicken embryos, which is interesting because our preliminary data shows that chicken Sox10 is sufficient to induce the expression of other neural crest markers when expressed in quail. We induced chicken Sox10 in quail embryos and found it induced premature NC migratory cells, indicating Sox9 and Pax7. These studies increase our understanding of the mechanisms mediating NC development in vertebrates and highlight new tools that can be used in evolutionary development research.