Collaborative Proposal: Local adaptation across latitudes: spatial scales, gene flow, and correlates of countergradient growth variation

智力优点：适应性遗传变异的地理模式知识对物种保护至关重要，但在海洋系统中，我们对这种现象的理解几乎为零。 直到最近，人们一直认为，由于大多数海洋物种的生命阶段高度分散或移动的，只有在广泛的地理范围内才能发生地方适应。这一观点是支持相对较低水平的遗传变异种群之间的DNA标记中立选择的调查索引。表型变异预计主要是环境起源，特别是对环境条件高度敏感的生理性状。 在对大西洋银汉鱼（Menidia menidia）和其他物种的研究的刺激下，这些长期持有的信念正在迅速改变。 银汉鱼在一套共同进化的生理和形态特征中显示出高度结构化的局部适应的戏剧性证据，这些特征与北美东海岸沿着纬度的气候变化密切相关。然而，分子遗传学调查的初步数据表明，在整个纬度范围内存在着广泛的基因流动沿着。该项目将解决两个核心问题。第一个问题涉及当地适应的微观地理。 有多精细？ 它是如何受到基因流的影响？ 它是否与海岸线的物理特征密切相关？ 多个性状在同一梯度上沿着相似地共同变化吗？ 第二个问题集中在生长速度的演变，强烈显示逆梯度纬度变化不仅在银汉鱼，但也在许多其他类群的特点。 最近的实验表明，生长率可以根据大小选择性死亡率，包括捕捞造成的遗传变化，迅速演变。 本项目将研究增长率演变的相关性。 我们将研究如何权衡与生长速度的影响发展，行为，形态和动物抵御疾病的能力。这项研究整合了地理学、生理学、定量和分子遗传学、行为学、免疫学和发育生物学。 它利用自然和实验进化的种群，从而允许严格测试假设，这在大多数其他海洋物种中是不可能的。 更广泛的影响：该项目将一名高级调查员的经验与两名新兴的少数族裔背景的初级教员的技能结合起来。 参与该项目的学生将有独特的机会体验海洋保护的生态和分子遗传方法。 由于在亚麻池塘海洋实验室的银汉鱼圈养种群的持续维护和可用性，该项目提供了通过学生研究项目，课堂演示和图尔斯旅游参与科学的公众极好的机会。 此外，我们最近关于大小选择性捕捞的进化影响的研究结果在全世界引起了广泛的宣传和兴趣，这是一个极好的机会，可以增加公众对进化原理及其如何影响当代社会问题的理解。

Intellectual merit: Knowledge of geographic patterns in adaptive genetic variation is crucial to species conservation, yet in marine systems our understanding of this phenomenon is virtually nil. Until recently, the belief has been that because most marine species have highly dispersive or mobile life stages, local adaptation could occur only on broad geographic scales. This view is supported by comparatively low levels of genetic variation among populations as indexed by surveys of DNA markers neutral to selection. Phenotypic variation is expected to be largely of environmental origin, especially for physiological traits that are highly sensitive to environmental conditions. Stimulated by studies of the Atlantic silverside (Menidia menidia) and other species, these long-held beliefs are rapidly changing. The silverside shows dramatic evidence of highly structured local adaptation in a suite of coevolving physiological and morphological traits tightly associated with climate change across latitudes along the east coast of North America. Yet preliminary data from molecular genetic surveys suggest extensive gene flow along the entire latitudinal range. This project will address two central problems. The first concerns the micro-geography of local adaptation. How finely scaled is it? How is it influenced by gene flow? Is it closely tied to physical features of the coastline? Do multiple traits co-vary similarly along the same gradient? The second problem focuses on the evolution of growth rate, a trait that strongly displays countergradient latitudinal variation not only in the silverside but also in numerous other taxa. Recent experiments show that growth rate can evolve very rapidly in response to size-selective mortality, including genetic changes caused by fishing. This project will examine the correlates of growth rate evolution. We will study how trade-offs with growth rate influence development, behavior, morphology, and the ability of animals to defend against disease. This research integrates biogeography, physiology, quantitative and molecular genetics, behavior, immunology, and developmental biology. It draws upon natural and experimentally evolved populations, thereby allowing rigorous testing of hypotheses that would be impossible in most other marine species. Broader Implications: This project unites the experience of a senior investigator with the skills of two emerging junior faculty of minority background. Students working on the project will have a unique opportunity to experience both ecological and molecular genetic approaches to marine conservation. Because of the continuous maintenance and availability of captive populations of the silverside at the Flax Pond Marine Laboratory, this project provides excellent opportunities for engaging the public in science through student research projects, class demonstrations, and tours. In addition, the extensive worldwide publicity and interest generated by our recent findings on evolutionary effects of size-selective fishing represent an excellent opportunity to increase public understanding of the principles of evolution and how they affect contemporary societal issues.