The Phylogeny and Evolution of Cetacea: Resolution of Rapid Radiations and a Molecular Blueprint for Modern Whales, Dolphins, and Porpoises

鲸目动物的系统发育和进化：快速辐射的解析和现代鲸鱼、海豚和鼠海豚的分子蓝图

• 批准号: 1457735
• 负责人: Mark Springer
• 金额: $ 61.48万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457735&HistoricalAwards=false
• 关键词: Phylogeny; Evolution; Cetacea; Resolution; Rapid

The evolutionary origin of Cetacea (whales, dolphins, and porpoises) in the Eocene, 50 million years ago, ranks among the best-documented macroevolutionary transitions. To non-scientists, this move from a terrestrial habitat to a committed aquatic lifestyle might seem improbable, yet the wholesale changes in anatomy required for this transformation are recorded in the fossil record. With the advent of genomics, it is now possible to study this remarkable evolutionary change at the molecular level. In this project, researchers will document the genetic basis of traits that were altered in the evolutionary genesis of these secondarily aquatic mammals and trace the molecular changes that produced a modern whale. In this project, researchers will train a postdoctoral scholar, graduate students, and multiple undergraduate interns at UC Riverside, a minority serving institution. The ethnically diverse makeup of UC Riverside provides an opportunity to bring cutting edge research to students who are historically underrepresented in science. Results from the research also will be incorporated into coursework and provide content for museum displays focused on evolutionary principles. Grant participants, including students, will collaborate with staff at the San Diego Natural History Museum to relate exciting research breakthroughs in a revitalized 'Fossil Mysteries' exhibit with bilingual educational modules.For Cetacea, standard phylogenetic analyses of fossil and molecular data have been used to reconstruct major phenotypic transformations in the group, with fossils providing signposts that place key evolutionary innovations relative to Earth history. Yet, despite ongoing phylogenetic studies based on large datasets, a fully resolved reconstruction of cetacean evolution has been elusive. The researchers propose a three-pronged approach to an enhanced study of cetacean evolutionary history that will utilize 500 genes to: 1) compare alternate approaches to the reconstruction of species trees using a robust sample of genetic data, 2) resolve problematic systematic relationships within Delphinidae (oceanic dolphins), Phocoenidae (porpoises), and Balaenopteroidea (rorquals and gray whale), 3) synthesize a phylogenomic blueprint for modern cetaceans. Exon capture and next generation sequencing methods will be employed to rapidly characterize candidate loci that represent genes predicted to have undergone adaptive or degenerative change. The researchers will target genes that are critical for behavioral and anatomical features that are highly derived in the group, including loci implicated in vision, hearing, olfaction, deep diving, aging, tooth development, baleen formation, and brain size. The end result will be the first, detailed, genomic characterization of a major macroevolutionary transition that is also documented by extensive fossil evidence.

鲸目动物（鲸鱼、海豚和鼠海豚）在 5000 万年前始新世的进化起源是记录最齐全的宏观进化转变之一。对于非科学家来说，从陆地栖息地到水生生活方式的转变似乎不太可能，但这种转变所需的解剖结构的大规模变化记录在化石记录中。随着基因组学的出现，现在可以在分子水平上研究这种显着的进化变化。在这个项目中，研究人员将记录这些次生水生哺乳动物的进化起源中改变的性状的遗传基础，并追踪产生现代鲸鱼的分子变化。在这个项目中，研究人员将在少数族裔服务机构加州大学河滨分校培训一名博士后学者、研究生和多名本科生实习生。加州大学河滨分校的种族多元化构成为向历史上在科学领域代表性不足的学生提供了前沿研究的机会。研究结果也将被纳入课程作业中，并为专注于进化原理的博物馆展示提供内容。包括学生在内的资助参与者将与圣地亚哥自然历史博物馆的工作人员合作，通过双语教育模块讲述复兴的“化石之谜”展览中令人兴奋的研究突破。对于鲸目动物，化石和分子数据的标准系统发育分析已被用于重建该群体的主要表型转变，化石提供了与地球历史相关的关键进化创新的路标。 然而，尽管基于大型数据集的系统发育研究正在进行中，但鲸目动物进化的完全解析重建仍然难以实现。研究人员提出了一种三管齐下的方法来加强鲸目动物进化史的研究，该方法将利用 500 个基因来：1）使用可靠的遗传数据样本比较重建物种树的替代方法，2）解决海豚科内有问题的系统关系（海洋海豚）、Phocoenidae（鼠海豚）和 Balaenopteroidea（须鲸和灰鲸），3) 综合系统发育组现代鲸类动物的蓝图。 将采用外显子捕获和下一代测序方法来快速表征候选基因座，这些候选基因座代表预测已经历适应性或退化变化的基因。研究人员将针对对该群体高度衍生的行为和解剖特征至关重要的基因，包括与视觉、听觉、嗅觉、深潜、衰老、牙齿发育、鲸须形成和大脑大小有关的基因座。 最终结果将是对主要宏观进化转变的第一个详细的基因组特征描述，大量化石证据也记录了这一转变。