Collaborative Research: Searching for Links Between Genotype and Phenotype in the Evolution of Air Breathing, Hypoxia, and Terrestriality in Gobies

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”本研究将调查弹涂鱼的空中呼吸和两栖能力，弹涂鱼以其离开水生活的能力而闻名。这项研究将探索弹涂鱼进化过程的遗传基础，从只在低氧环境条件下紧急呼吸空气的形式，到长时间离开水的形式，从而变得高度依赖空气呼吸。弹涂鱼辐射到生态位需要更高程度的陆生性，这与早期四足动物的进化序列相似，本研究将用弹涂鱼作为模型组，研究晚古生代（约3.8 - 2.5亿年前，mya）四足动物向陆地进化的生理方面的适应。在泥盆纪晚期（380- 360mya），大气氧含量较低（13-17%），而在石炭纪-早二叠世（360- 280mya），大气氧含量上升至30-35%。对弹涂鱼的研究将检验有关大气氧气水平影响脊椎动物陆地辐射的理论。这将通过测量环境氧气水平对弹涂鱼在封闭在大气室中的陆地跑步机上表现的影响来完成。此外，将对运动后的营养物质（葡萄糖）和代谢物（乳酸）、血液特性和其他代谢状态指标进行时间序列比较，这些指标将在陆地生活的专业化程度上有所不同。还需要研究的是弹涂鱼离开水的时间范围与其呼吸空气的能力之间的遗传联系。这将通过比较不同物种的基因表达谱如何因运动和长时间暴露在空气中而改变来完成。拟议的研究将涉及对本科生、研究生和博士后的培训和指导，从而继续促进教学、培训和学习。

"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.