"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." This study will investigate aspects of aerial respiration and amphibious capacity in mudskipper fishes (Family Gobiidae), which are renowned for their capacity to live out of water. The research will probe the genetic bases for the evolutionary progression of the mudskippers from forms that only used air-breathing as an emergency response to low environmental oxygen conditions to forms that spend extended periods out of water and thus have become highly dependent upon air breathing. The radiation of mudskippers into ecological niches requiring higher degrees of terrestriality parallels the evolutionary sequence of the early tetrapods and this study will employ mudskippers as a model group for investigating physiological aspects of the adaptations underlying the tetrapod progression onto land during the Late Paleozoic Era (~380-250 million years ago, mya). In the late Devonian Period (380-360 mya), atmospheric oxygen was low (13-17%) but then increased to 30-35% in the Carboniferous-Early Permian (360-280 mya). The research on mudskippers will test theories suggesting that atmospheric oxygen levels affected the vertebrate land radiation. This will be done by measuring the effect of ambient oxygen levels on mudskipper performance on a terrestrial treadmill enclosed in an atmospheric chamber. In addition, time-series comparisons of post-exercise levels of nutrients (glucose) and metabolites (lactic acid), blood properties, and other indices of metabolic state will be made for gobies that differ in their degree of specializations for terrestrial life. Also to be studied is the genetic link between the extent of time a mudskipper spends out of water and its capacity for air breathing. This will be done by comparing how the gene-expression profiles of different species are altered by exercise and prolonged air exposure. The proposed research will involve the training and mentoring of undergraduate, graduate, and post doctoral students and thus continue to promote teaching, training, and learning.
