Thermal Adaptation of Paramecium
Temperature is an all-pervasive environmental attribute that strongly influences the phenotype of organisms, their abundance and distribution, as well as population dynamics. In particular, the development and growth rate of ectotherms depend heavily on temperature, because of the strong temperature effect on biochemical reactions. Due to the observational evidence that global warming has a discernible influence on many biological systems, experimental investigations on the impact of elevated temperatures on ectotherms’ ecophysiology and genetic diversity has caused renewed interest.
Within this project, colleagues from Université de Montpellier and I were investigating patterns of evolutionary temperature adaptation at the molecular and phenotypic level in the protozoan Paramecium caudatum. These investigations aimed at predicting effects on the diversity and the response of P. caudatum to climate change making use of experimental evolutionary approaches. In a study published in Molecular Ecology, we have shown e.g., that populations evolving at high temperatures in experimental microcosms were more tolerant to acute heat stress and had higher fitness at optimum temperatures compared to control populations.
My colleagues are still seeking to better understand the evolutionary processes as well as the potential and constraints of rapid temperature adaptation in Paramecium. A hypothesis that is being addressed is e.g. that the genetic capability of ciliates for an epigenetic transition between phenotypes provides an adaptive advantage for a rapid adaptation to new environments. Combining genetic, transcriptomic and phenotypic analyses of laboratory selection experiments with eco-evolutionary modelling approaches will greatly help to shed some light on the underlying mechanisms.