NSF Postdoctoral Fellowship in Biology: Pleiotropic Role and Fitness Consequences of Single Genes in Mexican Cavefish (Astyanax mexicanus)

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2022, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the Fellow that will contribute to the area of Rules of Life in innovative ways. Caves are extreme environments and are often characterized by low oxygen, limited nutrient availability, and complete darkness.

Mexican tetra (Astyanax mexicanus) exist as surface dwelling and cave populations that exhibit adaptation to cave living including altered metabolism, reduced eyesight, sleep duration, and pigmentation. Using surface fish carrying mutations for candidate genes that impact cave-related traits, the Fellow will examine the multi-trait impact of single genes and their consequences on survival in the cave environment.

This research will produce a genotype-to-trait and genotype-to-fitness map for single genes and will inform the role of pleiotropic genes in adaptation to the extreme cave environment. The Fellow will leverage undergraduate research activities at the hosting institution (including a course-based research experience) that benefit students from groups underrepresented in STEM disciplines.

To understand the multi-trait impacts of single genes, the Fellow will measure cave-related traits including sleep architecture, melanophore size and number, metabolism, hypoxia tolerance, and circadian rhythms in surface fish carrying mutations for three candidate pleiotropic genes. Traits will be measured under fed and unfed conditions to examine plasticity in response to food availability, which is thought to be reduced in the cave environment.

Candidate gene fitness impacts will be examined using a mark-recapture field experiment in a self-contained man-made cave. Survival and body condition throughout the field experiment will be used to assess fitness of each mutant. Selection coefficients with predictive capability for evolutionary modeling will be produced.

The Fellow will be trained in physiological and behavioral assays and gene editing techniques. To broaden participation in science, the Fellow will 1) train undergraduate students from diverse backgrounds in research including physiological and behavioral assays, gene editing techniques, and computational biology, and 2) implement a tiered mentorship program among postdocs, graduate, and undergraduate students.

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.