INVESTIGATING THE GENETIC BASIS OF CAVEFISH EVOLUTION

 

We use the Mexican tetra, Astyanax mexicanus, to study how novel environments alter the genome and select for morphological and physiological traits

Cave-dwelling populations of Astyanax mexicanus evolved in a starkly different environment compared to their river-dwelling ancestors. Over 200,000 years ago, the fish invaded perpetually dark underground limestone caves in the Sierras of Northeastern Mexico. They adapted to a diet of bat droppings and flood debris while surface counterparts consumed plants and insects in abundance.  

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Cavefish have a very different appearance compared to surface fish although they are the same species. Most apparent, they have reduced pigment and lack eyes. They evolved an insatiable appetite and modified their metabolism to store more fat than surface fish. Some of their adaptations, like insulin resistance, are deadly in humans. Our lab is currently focused on how cavefish have altered their digestive system to maximize energy assimilation.

The Mexican tetra has emerged as a model system in part due to the growing number of methods and resources for analyzing gene function. We have used quantitative trait loci (QTL) mapping to identify genomic regions linked to altered nutrient accumulation and gut morphology. To uncover the types and locations of genetic changes responsible for cavefish adaptations we will combine comparative genomics, transcriptomics, and gene editing.

Image by CDC
 

Current projects are aimed at uncovering how evolution has modified

  • Gene regulatory networks that specify segments of the gut tube

  • Plasticity of intestinal stem cells in response to environmental cues

  • Development and function of the enteric nervous system 

 
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DEPARTMENT OF BIOLOGY
UNIVERSITY OF NEVADA, RENO

 
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MISTY RIDDLE PHD

Assistant Professor

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KAITLYN WEBSTER PHD

Postdoctoral Fellow

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DAVID PÉREZ GUERRA

Graduate Student

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PAVANI PONNIMBADUGE - PERERA

Graduate Student

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HEATHER WOODSON-GAMMON

Aquatics Technician

WE VALUE DIVERSITY

Our lab is committed to allyship for marginalized and underrepresented communities

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Some of the ways we are working to create an anti-racist environment in our group and promote diversity, inclusion, and equitable access to STEM education are:

  • Educating ourselves about racial injustice and systemic discrimination

  • Listening to and uplifting voices from marginalized communities

  • Speaking out and pushing for change when we see microaggressions or institutional policies that disadvantage marginalized communities, both within the lab and within the larger campus community

  • Making space and time for lab members to heal, take care of their communities, or fight for justice, and continuing to provide financial, career, and other support while they do so

  • Donating to or volunteering for organizations that promote the success and well-being of marginalized communities in STEM

  • Highlighting the contributions of underrepresented communities to STEM

  • Regularly discussing how to promote diversity in STEM during lab meetings

  • Acknowledging that the UNR is situated on the traditional homelands of the Numu (Northern Paiute), Wasiw (Washoe), Newe (western Shoshone), and Nuwu (Southern Paiute) peoples. These lands continue to be a gathering place for Indigenous Peoples, and we recognize their deep connections to these places. We extend our appreciation to live and learn on their territory.

  • Staying up to date on the initiatives, resources, and events organized by UNR office of Diversity and Inclusion

  • Coordinating our efforts with the EECB student Justice, Equity, Diversity, and Inclusion Committee (JEDI)


Image and some text adapted from Sammy Katta and EECB JEDI