Rapid adaptation and plasticity
Evolution is often considered a slow process taking hundreds to thousands of generations to affect population level change. This narrow expectation captures a limited set of conditions under which evolutionary processes occur. Recent studies have shown that wild populations can evolve over tens of generations in response to rapidly changing environmental conditions, including temperature although the genetic basis for rapid evolution remains poorly understood. The phenotypic response that ectothermic animals have to temperature implicates heritable metabolic processes as likely targets of evolution and may explain why organisms are able to readily evolve in response to rapidly changing environmental temperature.
Current: Metabolic and gene expression plasticity in Mexican tetra (Astyanax mexicanus)
A. mexicanus exist as two morphs: ancestral surface and ~30 independently derived cave populations. Cave morphs have evolved to survive in the constantly dark and nutrient limited cave environment and differ from surface morphs in their metabolism, behavior, and morphology including eye size/presence, mechano-sensory system, sugar and lipid metabolism, and degree of pigmentation. Planned experiments include gene expression response to starvation in surface and cave morphs and mark-recapture experiments to assess plasticity of sleep and metabolism in wild caught surface fish introduced into a man-made cave.
Past: Metabolic and thermal physiology, gene expression, and genomics
My dissertation work was largely interdisciplinary and leveraged the large variation found within and among F. heteroclitus populations found within 10s of kilometers (similar to that found between species separated by 100s of kilometers living in distinct environments) to understand the molecular and genetic basis of thermal acclimation and local adaptation to temperature.
Other past projects included characterizing scope of response to constant and variable CO2 regimes in early life stage Atlantic silverside (Menidia menidia) as a NOAA Hollings Scholar and a collaboration quantifying gene expression response to Stony Coral Tissue Loss Disease (SCTLD) in two species of corals found on the Florida Reef Tract (press release).
DeLiberto A.N., Drown M.K., Ehrlich M.A., Oleksiak M.F., and Crawford D.L. (2022). Feeling the heat: Variation in thermal sensitivity within and among populations. Journal of Experimental Biology.
Chambers, R. C., Habeck, E., Boyce, D., Drown, M. K., Brewster, S., & Zyck, A. (2021). Scope of response of Atlantic silverside (Menidia menidia) to a broad range of constant and variable CO2 regimes. Internal Report.
Chambers, R. C., Habeck, E., Boyce, D., Drown, M. K., Wieczorek, D., & Poach, M. (2021). A new apparatus for revealing the biological scope-of-response of small marine organisms to multiple CO2 regimes. Internal Report.
Drown, M.K., DeLiberto, A.N., Ehrlich, M.A., Crawford, D.L., & Oleksiak, M.F. (2021). Interindividual variation in metabolic and thermal tolerance traits from populations subjected to recent anthropogenic heating. Royal Society Open Science.
Traylor-Knowles, N., Connelly, M.T., Young, B.D., Eaton, K., Muller, E.M., Paul, V.J., Ushijima, B., DeMerlis, A., Drown, M.K., Goncalves, A. and Kron, N. (2021). Gene Expression Response to Stony Coral Tissue Loss Disease Transmission in M. cavernosa and O. faveolata From Florida. Frontiers in Marine Science.
Drown, M.K., DeLiberto, A.N., Crawford, D.L., & Oleksiak, M.F. (2020). An innovative setup for high-throughput respirometry of small aquatic animals. Frontiers in Marine Science: Aquatic Physiology.