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Dissertation Research: Surviving the K/Pg Mass Extinction: the genome as a life history character in birds

论文研究：在 K/Pg 大规模灭绝中幸存：基因组作为鸟类生命史特征

基本信息

批准号：
1700786
负责人：
Irby Lovette
金额：
$ 2.02万
依托单位：
Cornell University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2019-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1700786&HistoricalAwards=false
关键词：
Dissertation Research Surviving Pg Mass

项目摘要

Birds are among the most charismatic and broadly appreciated groups of living organisms, but the early origins of the modern bird radiation remain shrouded in mystery. One particularly vexing problem concerns the age of birds. Estimates based on the rate of DNA evolution suggest modern birds started to evolve about 160 million-years ago; the fossil record however, suggests an age that is scarcely older than 66 million years. Explaining the ~100-million-year gap in the fossil record profoundly limits our ability to understand when, how, and why modern bird diversity came to be. This project examines disagreements between molecular divergence time analyses and the avian fossil record, and studies a new hypothesis to explain the observed discrepancy. The project synthesizes data from paleontological and genomic datasets with predictions from population genetic theory. This work also paves the way for an integrative approach to studying evolutionary patterns across other branches of the tree of life. Moreover, the study investigates the effects of the K/Pg (Cretaceous-Paleogene) mass extinction, with important implications for understanding the decimation of Mesozoic dinosaurs and their resurrection in the form of modern birds. Such work may reveal fundamental clues into how and when Earth's modern biodiversity arose. Finally, the researchers will take advantage of the diverse outreach mechanisms at the Cornell Lab of Ornithology to communicate their findings to a broad audience.In the first part of the project, the researchers will study the age of modern birds using a variety of simulation, empirical and theoretical approaches grounded in the study of systematics. The researchers will use recent developments in Bayesian modeling to test the hypothesis that transient miniaturization of body size in the wake of the K/Pg mass extinction can explain a period of molecular rate acceleration in the extinction's aftermath. In the second part of the project, the researchers will study the feasibility of reconstructing unknown life history traits from extant and extinct taxa, conditioned on inferred rates of molecular evolution. A key component of the work will be to advance expertise in distributed high performance computing for phylogenetics, and in analyzing data related to avian life history evolution. In general, the research will leverage the recognition that rates of genome evolution are an important axis of life history variation to promote a progressive approach to studying paleo-life history diversity, and enable the integration of historically disparate information sources. The research will have potentially broad significance to comparative biology and phylogenetics, and may influence the field of divergence time analysis in both the short and long term.

鸟类是最具魅力和最受广泛认可的生物体群体之一，但现代鸟类辐射的早期起源仍然笼罩在神秘之中。一个特别令人烦恼的问题是鸟类的年龄。基于 DNA 进化速度的估计表明，现代鸟类在大约 1.6 亿年前开始进化；然而，化石记录表明其年龄仅超过 6600 万年。解释化石记录中约一亿年的差距极大地限制了我们理解现代鸟类多样性何时、如何以及为何出现的能力。该项目研究了分子分歧时间分析和鸟类化石记录之间的分歧，并研究了一个新的假设来解释观察到的差异。该项目综合了古生物学和基因组数据集的数据以及群体遗传理论的预测。这项工作还为研究生命之树其他分支的进化模式的综合方法铺平了道路。此外，该研究还调查了K/Pg（白垩纪-古近纪）大规模灭绝的影响，对于理解中生代恐龙的灭绝及其以现代鸟类的形式复活具有重要意义。此类工作可能揭示地球现代生物多样性如何以及何时产生的基本线索。最后，研究人员将利用康奈尔鸟类学实验室的多样化推广机制，向广大受众传达他们的发现。在该项目的第一部分，研究人员将使用基于系统学研究的各种模拟、经验和理论方法来研究现代鸟类的年龄。研究人员将利用贝叶斯模型的最新进展来检验这样的假设：K/Pg 大规模灭绝后身体尺寸的短暂缩小可以解释灭绝后一段时期的分子速率加速。在该项目的第二部分，研究人员将研究以推断的分子进化速率为条件，从现存和灭绝的类群中重建未知生命史特征的可行性。这项工作的一个关键组成部分将是提高系统发育学分布式高性能计算以及分析与鸟类生命史进化相关的数据方面的专业知识。总的来说，该研究将利用基因组进化速率是生命史变异的重要轴这一认识，促进研究古生命史多样性的渐进方法，并实现历史上不同信息源的整合。该研究将对比较生物学和系统发育学具有潜在广泛的意义，并可能在短期和长期影响分歧时间分析领域。