Rohner Lab

Observing all the beautiful variation in the animal kingdom, including us humans.




Why Cavefish?

The Rohner lab is interested in all the beautiful variation we can observe in the animal kingdom, including us humans. We are investigating the general genetic mechanisms and particular mutations underlying this tremendous diversity in morphology, physiology, and behavior.

Understanding the genetic basis of adaptation has broad applications not only for a basic understanding of evolution but also for human pathologies given that many modern human diseases (e.g. diabetes, allergies, many types of cancer) are a consequence of being mis-adapted to modern society.

Distribution of the 29 known cavefish populations in Mexico (white circles).
C, D show some exemplary habitats of the ones we are currently studying (F-H).

We are mostly using the cavefish system Astyanax mexicanus as a model system to address the genetic basis of adaptation because of its clear ecological adaptation scenario, its multiple interfertile populations and the ability to breed and live in the laboratory.

Stowers Aquatics Core cavefish facility located next to the Rohner Lab.

Our custom built state-of-the-art Pentair systems (10 racks) are individually monitored and controlled to ensure the best health, growth and breeding success of several thousand cavefish.

Model Organism

The cavefish Astyanax mexicanus is an exciting model organism that provides us with a clear ecological adaptation scenario, the adaptation to the subterranean cave environment. The model is perfect to study the combination of environment and the resulting variation, given the direction of evolution and adaptation is known (from surface to cave) and the environment of the cave provides reasonably well defined environmental parameters such as the lack of light, the scarcity of food, and the absence of predators.

The beauty of this system lies in the fact that both forms coexist in nature and are still interfertile, despite their gross differences in morphology, physiology, and behavior, allowing for genetic (e.g. Quantitative Trait Loci - QTL) and developmental studies. Additionally, there are numerous independently evolved cave populations that have converged on the cave-morph phenotype, each of which is the result of a replicated natural experiment, making it an ideal system to study parallelism and convergence.


Among the biggest challenges for animals in a cave environment is the scarcity of food. Since caves are completely dark, no primary photosynthetic producers can survive in this extreme environment. Therefore, cavefish dependent from food sources outside of the caves, mostly input from bats and seasonal flooding. Given the unpredictability of such food sources, cavefish have adapted to long starvation periods and optimized their metabolism accordingly.

For example cavefish have increased their appetite, enlarged fat reservoirs, and altered fat and lipid deposition. Despite these impressive changes to their metabolism, cavefish remain healthy, fertile and do not show any sign of distress, even when fed high fat diets.

Surface and cave form of Astyanax mexicanus.

We are aiming to study the genetic basis of these physiological alterations in order to understand adaptation to nutrient poor environments with the ultimate goal of finding ways to counteract our own health problems which arise as a consequence of living under conditions we are not adapted to.

Research Summary

Lab Members

Feel free to email us if you have any questions about our cavefish research or current openings in the Rohner Lab.

Nicolas Rohner



Stacey Williams
Senior Administrative Assistant

Karin Zueckert-Gaudenz
Lab Manager

Jenny Sung

Jaya Krishnan
Postdoctoral Research Associate

Robert Peuss
Postdoctoral Research Associate

Shaolei Xiong
Graduate Researcher

Lab Alumni

Abagael Sykes
Summer Scholar

Rebecca Richmond-Smith
Summer Scholar

Jennifer Rutkowski
Summer Scholar

Alice Bedois
Summer Scholar

Aubrey Kent
Summer Scholar

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