GxE Interactions

The maintenance of genetic variation within populations is essential to retaining evolutionary potential in the face of novel selection pressure. Selection and drift should tend to reduce genetic variation. The mechanisms by which variation is maintained within populations are still not well understood. We have recently demonstrated two different gene-by-environment interactions between fitness-related traits and two ubiquitous environmental variables (temperature and food) in the variable platyfish, Xiphophorus variatus. GxE interactions maintaining intra-population genetic variation have been widely supported by evolutionary theory, but rarely documented in nature. Ongoing work will continue to investigate the physiological and genetic mechanisms that mediate changes in performance of traits such as thermal tolerance and energetic state under different environmental conditions. In addition to addressing a key evolutionary question, fluctuating fitness in response to thermal and resource stress demonstrate potential consequences of global climate change on genetic variation, making X. variatus an interesting system to investigate physiological response to global change.