EAR-PF Ancient DNA meets modern genomes: An exploration of diatom evolution, ecology, and environmental change in the Yellowstone Basin

Trisha L Spanbauer博士已获得NSF博士后奖学金，在德克萨斯大学奥斯汀分校开展研究和教育计划。该项目旨在通过使用现代和化石遗传材料评估微生物的进化和分化。在这样做的同时，这项研究还将调查隐藏的浮游植物多样性与古老的DNA（aDNA）分析和测试保存的aDNA在大型淡水湖泊。这个跨学科的项目结合了古生物学的方法来研究形态学的变化与下一代分子遗传学工具，以探索过去的进化变化，在最近分化的硅藻物种。为了让公众参与这一项目的成果，将通过德克萨斯大学奥斯汀分校的德克萨斯纪念博物馆在全年的特别活动中进行宣传。该项目的教育目标包括为中学教师提供免费研讨会，为本科生提供学习模块，让本科生参与研究，并为高年级本科生提供古生态学和古气候学讲座。黄石湖的“Stephanodiscus yellowstonensis”从“Stephanodiscus niagarae”的前身进化而来，是硅藻物种形成的一个有文献记载的极好案例。 本项目将通过瓣膜形态随时间变化的最大似然模型研究“Stephanodiscus yellowstonensis”的进化，并通过aDNA探索遗传进化。在串联，这些分析将阐述硅藻的形态和分子进化的模式和步伐。此外，该项目还将利用aDNA探索黄石湖中隐藏的浮游植物多样性，并确定aDNA保存和降解的任何问题。前者将允许在全新世的古生态淡水社区扩大了解，后者将有助于划定的好处和限制的aDNA作为一个紧急代理的环境变化。这种方法的转换组合允许将微观进化变化与宏观进化结果联系起来。形态进化提供的历史框架将丰富解释最近分化的微生物的aDNA的能力。此外，拟议的项目有可能进一步开发aDNA作为古湖泊学代理和分子进化工具。

Dr. Trisha L Spanbauer has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at the University of Texas at Austin. This project seeks to assess the evolution and differentiation of microorganisms by using modern and fossil genetic material. While doing so, this study will also investigate hidden phytoplankton diversity with ancient DNA (aDNA) analysis and test the preservation of aDNA in large freshwater lakes. This interdisciplinary project combines paleontological methodology to investigate morphological changes with next-generation molecular genetics tools to explore past evolutionary changes in a recently diverged species of diatom. To engage the public in the outcomes of this project, outreach will be provided through the University of Texas at Austin's Texas Memorial Museum at special events throughout the year. The projects educational goals include free workshops for middle school teachers, learning modules for undergraduate classes, engaging undergraduates in the research, and lectures on paleoecology and paleoclimatology for upper-level undergraduate classes.The evolution of "Stephanodiscus yellowstonensis" from a "Stephanodiscus niagarae" predecessor in Yellowstone Lake is an excellent documented case of diatom speciation. This project will investigate the evolution of "Stephanodiscus yellowstonensis" through maximum likelihood modeling of the valve morphology through time, and exploring the genetic evolution through aDNA. In tandem, these analyses will elaborate on the mode and pace of both morphological and molecular evolution in diatoms. In addition, this project will use aDNA to explore hidden phytoplankton diversity in Yellowstone Lake and to determine any issues with the preservation and degradation of aDNA. The former will allow for expanded understanding of the paleoecological freshwater community during the Holocene and the latter will help to delineate the benefits and limitations of aDNA as an emergent proxy of environmental change. This transformational combination of approaches allows for the linking of microevolutionary changes to macroevolutionary outcomes. The historical framework provided by the morphological evolution will enrich the ability to interpret the aDNA of a recently diverged microorganism. Additionally, the proposed project has the potential further develop aDNA as a paleolimnological proxy and molecular evolutionary tool.