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.

鸟类是最具魅力和广泛欣赏的活生物体之一，但现代鸟辐射的早期起源仍然笼罩在神秘之中。一个特别烦人的问题是鸟类的年龄。基于DNA进化率的估计表明，现代鸟类大约在16000万年前开始发展。但是，化石记录表明，这个年龄几乎不超过6600万年。在化石记录中解释了约1亿年的差距，严重限制了我们了解何时，如何以及为什么出现现代鸟类多样性的能力。该项目研究了分子差异时间分析与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。该项目将来自古生物学和基因组数据集的数据与人群遗传理论的预测进行了预测。这项工作还为整合方法铺平了道路，以研究生命树的其他分支之间的进化模式。此外，该研究还研究了K/PG（白垩纪 - 果仁）的质量灭绝的影响，对理解中生代恐龙的衰减及其复活具有重要意义。这样的工作可能揭示了地球现代生物多样性如何以及何时出现的基本线索。最后，研究人员将利用康奈尔（Cornell）鸟类学实验室的各种外展机制，将其发现传达给广泛的受众。研究人员将使用贝叶斯建模的最新发展来检验以下假设：在K/PG质量灭绝之后，体型的瞬时小型化可以解释灭绝后的分子速率加速度。在该项目的第二部分中，研究人员将研究从现存和灭绝的分类单元重建未知的生活历史特征的可行性，并取决于推断的分子进化率。这项工作的关键组成部分是提高系统发育分布式高性能计算的专业知识，并分析与鸟类生活历史演变有关的数据。通常，该研究将利用这样的认识，即基因组进化的速度是生活历史变化的重要轴，以促进一种渐进式方法来研究古生活历史多样性，并能够融入历史上不同的信息来源。该研究对比较生物学和系统发育学具有潜在的广泛意义，并可能影响短期和长期分析的差异时间分析。