Cave animals adapted to an extreme hostile environment that is perpetually dark, nutrient poor, and isolated. How do they do it? In our lab, we are studying the biology of cave-adaptation in the blind Mexican cavefish: Astyanax mexicanus. This species is unique in the sense that it is comprised of two morphotypes: an ancestral surface fish with eyes, and a blind, cave-adapted cavefish that evolved a suite of morphological and behavioral traits to survive in the caves. Another advantage the model brings is the availability of populations that are morphologically and behaviorally different, providing an opportunity to ask questions in the context of natural variation between populations within species.

1. What genes underlie evolution of social behaviors?

Epidemiological studies suggest that variations in sleep between individuals is associated with different tendencies towards aggression. However, the biological factors linking natural variation in sleep to aggression are largely unknown. Our laboratory leverages the natural variation in sleep and aggression present in A. mexicanus, to investigate this relationship. Here, we employ functional genetics, CRISPR/Cas9 gene editing, and behavioral approaches to uncover the contributions of specific allele variants to the evolution of sleep, aggression, and other social behaviors in fish.

2. Are ecological differences contributing to the plasticity of social behaviors?

Cavefish live in deep caves where standing water lies undisturbed for long periods of time, resulting in differences in ecological parameters. Our laboratory is addressing if environmental variations affect the plasticity of social behaviors in populations of surface fish and cavefish that come from dramatically different habitats. What happens when cavefish are raised under increased water temperatures? What happens if surface fish are raised in the dark? Is there plasticity of social behavior? Are sensory systems affected? What are neuro-circuits affected in the brain? Are there changes in gene expression associated to perpetual darkness?

3. What are the mechanisms underlying sensory system expansions in cavefish?

Cavefish evolved an enhanced mechanosensory system called the lateral line, possibly to compensate for the lack of vision. We are interested in identifying the genetic and developmental factors underlying mechanosensory enhancements in cavefish. Using confocal microscopy, transgenic lines, in-situ hybridization, immunohistochemistry, and CRISPR/Cas9 for knocking out candidate genes, trainees in our lab will be able to identify the biological mechanisms underlying variation of sensory systems between surface fish and cavefish, while associating these to the adaptation or plasticity of social behaviors.

Trainees in our laboratory will have the opportunity to participate and contribute to any of these projects. If interested in behavior evolution: project 1 is a great fit. If interested in environment, plasticity of behavior, and gene expression: project 2 is a great fit. If interested in fluorescence imaging and sensory neurobiology: project 3 is a great fit. If excited about research in evolution of complex traits altogether: all projects are a great fit.