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

在生命之树上，不同物种的饮食差异很大。一些物种的饮食非常特殊，只有一种或几种食物，而另一些物种似乎吃的食物范围很广。为什么一些动物有高度专业化的饮食，物种如何适应新的食物仍然是生物学领域的悬而未决的问题。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会对不同的食物资源变得专门。为了做到这一点，它将开发DNA测序的新应用，以产生关于饮食的数据，并开发分析复杂数据集的新方法。新方法将广泛适用于除青蛙以外的任何系统，由此产生的数据可以为其他主要的生物多样性问题提供洞察，例如为什么与温带地区相比，热带地区的物种更多。该项目将发展国际伙伴关系，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获取的数据，并产生基本的自然历史数据，这些数据可用于为濒危青蛙物种的保护战略提供信息。该研究项目将整合系统发育群落生态学和宏观进化的方法，以回答有关饮食进化和营养生态如何与多样性相关的问题。它将利用高通量测序来分析来自新大陆各地的青蛙的胃内容物。这项工作将生成一个识别到物种水平的猎物项目的数据集，其中包含有关青蛙饮食中每种猎物的相对丰度的信息。这项拟议的研究将使用猎物的线粒体基因组来构建猎物的系统发育树，并与将用基因组数据估计的青蛙的系统发育进行配对。利用这两棵树，将计算反映食物系统发育变异性和每种猎物类型的相对丰度的食物广度和重叠的衡量标准，并用于推断物种多样化和营养进化的速度。这些指标和估算率将被用来检查蛙类饮食的系统发育保守性，饮食专业化对物种形成的影响，以及营养进化速度和多样化速度之间的相关性。

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.