Long-term Research in Environmental Biology (LTREB): Rapid evolution of a Threespine Stickleback Population

进化史通常是通过比较几千到几百万代前拥有共同祖先的物种来研究的，但进化过程的研究是在相对较少的世代中进行的。因此，对过程的研究得出的结论必须通过时间和物种间的推断来解释历史。这个项目利用了一个独特的关于刺鱼的研究系统，以便直接将进化历史和过程结合起来。20世纪80年代，一个海上刺鱼种群在阿拉斯加的一个湖泊上定居下来，S随后经历了快速的进化。当1990年首次取样时，它在身体形状和大小、鳃盖的形状、盔板、摄食结构以及控制盔甲和调节体液中盐分浓度的基因上与海上刺鱼非常相似。每年的采样显示，每一个特征都朝着年老的湖泊种群逐渐进化变化，现在几乎无法区分。该项目将继续对这一湖泊种群进行长期研究，并扩大研究淡水湖中常见病原体对鱼类免疫进化的工作。该项目还启动了对处于淡水湖殖民最早阶段的额外海上刺鱼种群的新研究。这些海上种群的进化模拟了自上一个冰河时代以来无数淡水种群进化的历史。这项研究对预测鱼类物种在面对全球气候变化和密集捕捞对商业物种的压力时的适应性具有更广泛的相关性。它还将提供关于对新出现的传染病的免疫反应进化的有价值的信息。该项目为本科生提供了实践研究经验。该项目的数据将每年公布在一个可供公众访问的网站上，记录快速进化的鱼类收藏的时间序列将存放在耶鲁皮博迪博物馆供进一步研究。

Evolutionary history is generally studied by comparing species that shared a common ancestor thousands to millions of generations ago, but evolutionary processes are studied over relatively few generations. Hence, conclusions from studies on processes must be extrapolated through time and among species to interpret history. This project makes use of a unique study system involving the stickleback fish, in order to directly integrate evolutionary history and process. A sea-run stickleback population colonized an Alaskan lake in the 1980's and subsequently underwent rapid evolution. When first sampled in 1990, it closely resembled sea-run sticklebacks in body shape and size, the shape of the gill cover, armor plates, feeding structures, and the genes that control armor and regulate the salt concentration in body fluids. Annual sampling revealed progressive evolutionary change of every trait towards those of older lake populations, from which it is now almost indistinguishable. This project will continue the long term study of this lake population, and expand the work to study the evolution of fish immunity to disease agents that are prevalent in freshwater lakes. This project also initiates new research on additional sea-run stickleback populations that are at the earliest stages of colonization of freshwater lakes. Evolution of these sea-run populations simulates the history by which countless freshwater populations have evolved since the last ice age. This study has broader relevance to predicting the adaptability of fish species in the face of global climate change and intensive fishing pressure on commercial species. It will also provide valuable information on the evolution of immune response to emerging infectious disease. The project gives undergraduate students hands-on research experience. Data from this project will be posted annually on a publically accessible website, and the time series of fish collections documenting rapid evolution will be deposited in the Yale Peabody Museum for further study.