MCA: The neural and genetic architecture underlying lateral line evolution and development in cavefish

The overall goal of this project is to better understand how the nervous system evolves. By linking traditionally separate fields of genetics and neuroscience, the researchers will reveal how sensory systems change over time in the blind Mexican cavefish. The cavefish is a special animal in that it has both blind and eyed populations, thereby providing a unique opportunity to connect basic, fundamental research with a broader understanding of evolution for society (through journal publications, textbook chapters, popular press coverage etc.). The results of this work will generate new techniques and ideas that can be used to better understand how genetic variation contributes to neural processing in naturally evolved populations. In addition, this work on how the hair cell system processes information will provide insight into human auditory and vestibular (sense of balance) systems, as well as inspire engineers seeking to design efficient, low-cost sensors in autonomous vehicles. Furthermore, the researchers will present their work to the thousands of K-12 students who participate in the Whitney Lab’s Scientist for a Day Program, enhancing scientific literacy in Florida. New content on “sensory brains” will be developed for the YouTube channel, Fish Code Studios (established in 2014), that reaches a global audience, with 11,700+ subscribers and over 450,000 views and will continue to serve as a major public outreach platform. Researchers will investigate how selection influences sensory detection and modulation by applying powerful physiological and genetic approaches to an emerging model system for neural evolution. Combining electrophysiology and genome wide analyses of genetic architecture, investigations will reveal how the cavefish lateral line system evolved to enable prey capture. Aim 1 will focus on neurophysiology underlying variation in lateral line sensitivity across development. The lateral line system in fishes consists of mechanosensitive neuromasts distributed across the body, with the hair cells of each neuromast connected to afferent neurons that relay information to the brain. This information is simultaneously regulated by an efferent feedback circuit to enhance flow signals during swimming. Using in vivo patch clamp recordings, lateral line sensitivity in surface and cavefish populations will be defined to test whether evolutionarily derived changes in lateral line physiology have enhanced the sensory capabilities of cavefish. This will be done for the first time across developmental stages in larval cavefish. Aim 2 will involve a comprehensive genome wide analysis of genetic architecture regulating lateral line-mediated prey capture behavior. To identify the genetic architecture associated with lateral line differences, F2 surface-cave hybrid fish will be generated and the relationships between quantitative genetics and behavior will be measured. Genotyping-by-sequencing and high-resolution quantitative trait locus (QTL) mapping will be used to identify genomic regions associated with lateral line function and prey-capture behavior. This aim will determine the relationship between lateral line genetics and biomechanical differences in behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.