The contribution of gut microbiome composition to natural variation in sleep and aggression across populations in the blind Mexican cavefish

Project Summary Sleep and aggression are two complex behaviors that have recently been found underlying the emergence of neuropsychiatric disease. While large efforts have focused on genetic and environmental factors underlying variation in sleep and aggression, a missing puzzle piece is whether the gut microbiota contributes to these changes. Our goal is to understand the relationship between gastrointestinal (GI) microbiota and natural variation of sleep and aggression. Understanding how differing GI microbiota across phenotypically distinct populations of the same species impact sleep patterns and aggression would provide a missing link between genetic and environmental variation in the production of complex behaviors. To test this, we turn to the Mexican tetra, Astyanax mexicanus, a fish species comprised of two morphotypes with variable behavioral phenotypes: river-dwelling surface fish and blind cave-dwelling cavefish. Specifically, most populations of cavefish display reductions in sleep and aggression, while also exhibit variation of GI microbiota even in lab-reared conditions. Our central hypothesis is that GI microbiota influences the plasticity of sleep and aggression in surface fish and cavefish of the Mexican tetra. We designed 2 aims to directly test this hypothesis. In aim 1, we will ask how different dietary regimes impact microbial diversity associated to the gut in surface fish and cavefish, while correlating these with sleep and aggression. In aim 2, we will ask whether swapping GI microbiota between surface fish and cavefish through generating germ-free strains of each population will correlate with shifts in sleep and aggression. We expect lower nutritional value diets to impact GI microbial diversity and reduce sleep and aggression in surface fish but not cavefish, while sleep and aggression phenotypes will be reversed between the 2 ecotypes following swapping of GI microbiota. Taken together, we expect a strong correlation between GI microbial diversity and variation in sleep and aggression, potentially involving an interplay with neural circuitry during development in populations of A. mexicanus. Combining my expertise studying behavioral variation in A. mexicanus as a postdoc with my interest in uncovering the different levels underlying these changes which potentially include variation of the gut microbiome males me an ideal candidate to join and receive support from the new COBRE Center for Microbiomes Sciences at the University of Puerto Rico.