Phylogenomic Study of Adaptive Radiation in Antarctic Fishes

了解生物群体如何应对气候变化对于评估人类活动的影响以及了解过去的气候变化如何在很长一段时间内塑造生物多样性至关重要。占据南极洲附近近岸海洋栖息地的鱼类主要是一组称为Notothenioids的密切相关的物种。南极气候的剧烈变化似乎对这一经济上重要的鱼类谱系的起源和进化多样化很重要。南极洲的鱼类化石沉积物是在大陆经历温和的温度时形成的，表明该地区是鱼类谱系更加多样化的家园。今天，南大洋的沃茨非常寒冷，经常低于冰点，但南极鱼表现出许多适应性，以生活在这种恶劣的海洋栖息地，包括防冻蛋白的存在。该研究项目将从数百个基因中收集DNA序列，以推断几乎所有124种南极鱼的亲缘关系，并使用数学技术来估计物种和谱系的年龄。对南极类进化分歧时间的了解将使研究人员能够评估南极洲以前主要气候变化的时间是否与现代南大洋鱼类动物群形成中的关键事件相关。该项目还将进一步推动NSF的目标，即向公众提供科学发现和培训新一代科学家。该项目将通过自然历史博物馆展览和其他公共讲座，支持面向青少年团体和公众的教育推广活动。它将为研究生和博士后研究学者提供专业培训机会。适应性辐射，血统经历高速率的进化多样化与生态分歧相一致，主要是在岛屿生态系统中进行研究。Notothenioids占主导地位的鱼类区系的南大洋和展示抗冻糖蛋白，允许占领的零度以下的沃茨。Notothenioids被认为是海洋鱼类中适应性辐射的唯一例子之一，但对多样化和辐射到不同生态栖息地的进化历史知之甚少。这项研究将产生一个物种的进化史（进化史）几乎所有的124个公认的notothenioid物种，探讨适应性辐射在这个谱系的机制。通过使用下一代DNA测序和相关技术采样的约350个基因推断出遗传学。博物馆标本的形态测量数据，以调查形态多样化的克里思，并确定是否有谱系多样化和形态差异的起源之间的相关性。的模式的谱系，形态和生态多样性的notothenioid辐射将比较古气候记录，以确定过去的全球气候变化的情况下，形成了这个谱系的极地适应鱼类的进化多样化。

Understanding how groups of organisms respond to climate change is fundamentally important to assessing the impacts of human activities as well as understanding how past climatic shifts have shaped biological diversity over deep stretches of time. The fishes occupying the near-shore marine habitats around Antarctica are dominated by one group of closely related species called notothenioids. It appears dramatic changes in Antarctic climate were important in the origin and evolutionary diversification of this economically important lineage of fishes. Deposits of fossil fishes in Antarctica that were formed when the continent was experiencing milder temperatures show that the area was home to a much more diverse array of fish lineages. Today the waters of the Southern Ocean are very cold, and often below freezing, but notothenioids fishes exhibit a number of adaptions to live in this harsh set of marine habitats, including the presence of anti-freeze proteins. This research project will collect DNA sequences from hundreds of genes to infer the genealogical relationships of nearly all 124 notothenioid species, and use mathematical techniques to estimate the ages of species and lineages. Knowledge on the timing of evolutionary divergence in notothenioids will allow investigators to assess if timing of previous major climatic shifts in Antarctica are correlated with key events in the formation of the modern Southern Ocean fish fauna. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. The project will support educational outreach activities to teenager groups and to the general public through a natural history museum exhibit and other public lectures. It will provide professional training opportunities for graduate students and a postdoctoral research scholar. Adaptive radiation, where lineages experience high rates of evolutionary diversification coincident with ecological divergence, is mostly studied in island ecosystems. Notothenioids dominate the fish fauna of the Southern Ocean and exhibit antifreeze glycoproteins that allow occupation of the subzero waters. Notothenioids are noted as one of the only examples of adaptive radiation among marine fishes, but the evolutionary history of diversification and radiation into different ecological habitats is poorly understood. This research will generate a species phylogeny (evolutionary history) for nearly all of the 124 recognized notothenioid species to investigate the mechanisms of adaptive radiation in this lineage. The phylogeny is inferred from approximately 350 genes sampled using next generation DNA sequencing and related techniques. Morphometric data are taken for museum specimens to investigate the tempo of morphological diversification and to determine if there are correlations between rates of lineage diversification and the origin of morphological disparity. The patterns of lineage, morphological, and ecological diversification in the notothenioid radiation will be compared to the paleoclimatic record to determine if past instances of global climate change have shaped the evolutionary diversification of this lineage of polar-adapted fishes.