REU: Phenotypic Diversification in Gasterosteus

在最后一次更新世冰川推进期间，冰覆盖了三刺棘鱼（Gasterosteus aculeatus）的大部分现代活动范围。大约1.4万年前，随着冰川开始消退，形成了多种淡水栖息地，随后被海洋三刺棘鱼占领。今天，由此产生的淡水种群正在整个北美西北部经历着快速的进化多样化，在某些情况下已经发生了物种形成。这一引人注目的最新辐射为提供有关进化变化的模式和机制的信息带来了巨大的希望。它还为具有新属和高级分类群的适应性辐射提供了一个模型。拟议的研究将首次确定海洋三刺棘鱼所表现出的繁殖行为模式，以及它们在不同地点之间的差异程度。这对于解释辐射变化的模式是至关重要的，因为海洋形式被认为产生了今天观察到的不同的淡水形式。此外，还将记录20多个阿拉斯加淡水种群的生殖行为多样性。这些观察结果不仅将提供阿拉斯加淡水种群行为多样化范围的初步近似，而且将使研究人员能够为未来特定行为表型进化的研究选择种群。

During the last Pleistocene glacial advance, ice covered much of the modern day range of the threespine stickleback (Gasterosteus aculeatus). As the glaciers began to retreat about 14,000 years ago, a diversity of freshwater habitats were created and subsequently colonized by the marine threespine stickleback. Today, the resultant freshwater populations are undergoing rapid evolutionary diversification throughout northwestern North America, and in some cases speciation has occurred. This remarkable, recent radiation holds great promise for providing information on the patterns and mechanisms of evolutionary change. It also provides a model for adaptive radiations that have new genera and higher taxa. The proposed research will determine, for the first time, the reproductive behavior patterns exhibited by marine threespine stickleback, and the extent to which they vary among sites. This is essential for interpreting the patterns of change in the radiation because the marine form is thought to have given rise to the divergent freshwater forms observed today. In addition, the diversity of reproductive behavior in twenty or more Alaskan freshwater populations will be documented. These observations will not only provide a first approximation of the range of behavioral diversification among Alaskan freshwater populations, but will enable the investigators to select populations for future research on the evolution of specific behavioral phenotypes.