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 had a discernible influence on many biological systems, experimental investigations on the impact of elevated temperatures on ectothermsecophysiology and genetic diversity has caused renewed interest.

Within this project we are investigating patterns of evolutionary temperature adaptation at the molecular and phenotypic level in the protozoan Paramecium caudatum. These investigations aim to predict effects on the diversity and the response of P. caudatum to climate change making use of experimental evolutionary approaches. In a recent 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.

Future attempts are seeking to better understand evolutionary processes as well as the potential and constraints of rapid temperature adaptation in Paramecium. We address, for example, the hypothesis that the genetic capability of ciliates for an epigenetic transition between phenotypes provides an adaptive advantage for a rapid adaptation to new environments. We are also interested in the mechanisms determining the speed of adaptation under different timescales of evolutionary change. These investigations should combine genomic, transcriptomic and phenotypic analyses of laboratory selection experiments with eco-evolutionary modelling approaches.