DISSERTATION RESEARCH: A phylogenomic window into trophic niche evolution in frogs

在整个生命之树中，不同物种的饮食差异很大。有些物种有非常专门的饮食，只包括一种或几种食物，而其他物种似乎吃各种各样的食物。为什么有些动物有高度专门化的饮食和物种如何适应新的食物仍然是生物学领域的未解之谜。这个项目将使用青蛙作为一个研究系统，以了解动物如何以及为什么对不同的食物资源变得专业化。为此，它将开发DNA测序的新应用，以生成饮食数据和分析复杂数据集的新方法。新方法将广泛适用于青蛙以外的任何系统，由此产生的数据可以深入了解其他主要的生物多样性问题，例如为什么热带地区的物种多于温带地区。该项目将发展国际合作伙伴关系，为密歇根大学的本科生提供研究培训，为未来的科学研究产生大量可公开访问的数据，并产生基本的自然历史数据，可用于为濒危青蛙物种的保护策略提供信息。本研究项目将整合系统发育群落生态学和宏观进化的方法，以回答有关青蛙物种进化的问题。饮食和营养生态学如何与多样化相关。它将利用高通量测序来分析来自新世界各地的青蛙的胃内容物。这项工作将产生一个数据集的猎物项目确定到物种水平的信息相对丰富的每一个青蛙的饮食。拟议的研究将使用猎物项目的线粒体基因组来构建猎物的系统发育树，以与将使用基因组数据估计的青蛙的系统发育配对。有了这两棵树，饮食的宽度和重叠，反映在饮食和每种猎物类型的相对丰度的系统发育变异的措施将被计算和用于推断物种多样化和营养进化的速度。这些指标和估计率，然后将被用来检查系统发育保守性的青蛙饮食，饮食专业化对物种形成的影响，以及营养进化率和多样化率之间的相关性。

Across the Tree of Life, diet varies widely among species. Some species have very specialized diets that consist of only one or a few items, while other species appear to eat a broad range of food items. Why some animals have highly specialized diets and how species adapt to new food items remain unanswered questions in the field of biology. This project will use frogs as a study system to understand how and why animals become specialized on different food resources. To do so, it will develop new applications of DNA sequencing to generate data on diet and new methods for analyzing complex datasets. The new methods will be broadly applicable to any system beyond just frogs and the resultant data can provide insight into other major biodiversity questions, such as why there are more species in the tropics compared to temperate areas. This project will develop international partnerships, provide research training to undergraduate students at the University of Michigan, generate large quantities of publicly accessible data for future scientific research, and produce basic natural history data that can be used to inform conservation strategies for endangered frog species.This research project will integrate methods from phylogenetic community ecology and macroevolution to answer questions about the evolution of diet and how trophic ecology correlates with diversification. It will utilize high-throughput sequencing to analyze stomach contents of frogs from sites across the New World. This work will generate a dataset of prey items identified to species level with information about the relative abundance of each in a frog's diet. The proposed research will use the mitochondrial genomes of the prey items to construct a phylogenetic tree of the prey to pair with a phylogeny of frogs that will be estimated with genomic data. With these two trees, measures of diet breadth and overlap that reflect the phylogenetic variability in the diet and the relative abundance of each prey type will be calculated and used to infer rates of species diversification and trophic evolution. These metrics and estimated rates will then be used to examine phylogenetic conservatism in frog diet, the effect of dietary specialization on speciation, and the correlation between rates of trophic evolution and diversification rates.