Meeting Abstract
As a consequence of adapting to the cave environment, troglobitic organisms demonstrate a variety of extreme phenotypes. To explore the gene expression changes underlying these traits, we study the Mexican tetra, Astyanax mexicanus. This species, inclusive of surface and cave-dwelling morphs, provides a powerful comparative paradigm through which we can infer changes to the “ancestral” surface fish in the derived cavefish. Although many genes associated with cave adaptation have been identified through transcriptomic studies, their spatial and temporal expression remains unclear. In this study, we performed a series of in situ hybridization analyses (ISH) to assess distinct expression patterns between morphs. We focused on genes associated with neural crest specification, migration and differentiation. The neural crest plays a crucial role in the development of many variable traits between surface and cavefish, including the craniofacial complex, pigmentation and the peripheral nervous system. Utilizing stage-matched embryos across three developmental stages (24 hour post fertilization [hpf], 36 hpf, and 72 hpf), we probed several genes and observed substantial differences in expression in the early cranium and notochord. Current studies are evaluating the function of lesser known genes with different expression levels based on RNA-sequencing studies. This study provides qualitative evidence of early gene expression differences that putatively play a role in survival in the cave microenvironment.
