Meeting Abstract
While plasticity as long been recognized as an ubiquitous feature of organisms, plasticity’s role in influencing adaptive adaptation is increasingly being debated. Investigating how plasticity influences evolution has been challenging in natural populations because of the difficulty of capturing the dynamics during the early stages when populations are diverging. We overcome these challenges by studying the plasticity of gene expression in wild populations of Trinidad guppies (Poecilia reticulata) that have been experimentally introduced to predator free streams, which is a novel predatory state. We used RNASeq to measure the evolution of gene expression in the introduced populations, source population, and an already established low predation (target) population reared under common garden conditions. To test changes in plasticity fish were reared under ancestral conditions of predation and the novel condition of no predation. Gene expression was measured annually over the course of 3 years (10+ generations). Initial rapid evolutionary change in expression counter to the direction of ancestral plasticity and toward the target population was observed in the intro populations after 3-4 generations, supporting the theory of genetic compensation. Plasticity itself also decreased in the intro populations over this time. However, over longer time periods evolutionary divergence appears to slow, as plasticity decreased, suggesting that plasticity plays a vital role in rapid adaption to novel environments by altering the strength of selection acting on the population.
