Meeting Abstract

P1.140  Friday, Jan. 4  Phenotypic Plasticity and Adaptation in Fundulus Glycolytic Muscle Physiology DAYAN, DI*; OLESKIAK, MF; University of Miami, Miami FL ddayan@rsmas.miami.edu

Throughout their natural history, organisms become adapted to specific thermal environments, resulting in discrete ranges of temperatures at which physiological processes are optimized. For many organisms, however, body temperature fluctuates in a thermally variable environment. In response, organisms often reversibly alter their phenotype in a process termed phenotypic plasticity. Due to their diverse environmental distributions, known phylogeny and highly plastic traits, members of the fish genus Fundulus are excellent models to investigate the relationship between phenotypic plasticity and adaptation. We analyze glycolytic muscle gene expression profiles of two Fundulus species acclimated to a range of environmentally relevant temperatures using cDNA microarrays and find evidence of both evolution by natural selection and a robust acclimation response. Furthermore, gene-by-environment interactions make many evolved differences between populations apparent only under some environmental conditions. This observation is largely due to among population differences in phenotypic plasticity. The majority of genes that demonstrate a significant effect of acclimation or adaptation, however, are not shared. Neither process is dominant and plasticity and evolution appear to primarily operate orthogonally. Finally, these putatively adaptive differences may have functional consequences that are consistent with what is know about the thermal biology and ecology of this species providing many hypotheses for future physiological research.