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The Physiological Genomics of Diet Switching in Mammalian Herbivores

哺乳动物草食动物饮食转换的生理基因组学

基本信息

批准号：
1656497
负责人：
Michael Shapiro
金额：
$ 76.57万
依托单位：
University of Utah
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-01 至 2023-10-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1656497&HistoricalAwards=false
关键词：
Physiological Genomics Diet Switching Mammalian

项目摘要

At every meal, animals that feed on plants (herbivores) such as deer, cattle, and rabbits, face the possibility of being poisoned by naturally-occurring toxic chemicals in their food. Nevertheless, how herbivores process natural toxins remains poorly understood. For example, remarkably little is known about the specific genes that control an animal's ability to process potentially toxic compounds in plants. To address these fundamental problems, this research will focus on a dramatic dietary change: woodrats normally eat juniper and cactus, but several populations in the American southwest have switched to a diet of creosote bush. Creosote bush produces natural toxins that radically differ from juniper and cactus, and therefore the specialized woodrat populations must detoxify their diets differently than the juniper and cactus-eaters. The goal of this project is to identify DNA-level changes that are associated with woodrats' ability to feed on a toxic diet of creosote bush. This project will develop new genomic tools that will be useful to the broader scientific community. A better understanding of how animals process toxins can also impact decisions about pharmaceutical development for humans and other animals, and influence feeding options to improve production of free-ranging domestic herbivores like cattle. Results of this work will be communicated to the public through an interactive display about the ecology of woodrats at the Utah Museum of Natural History. Despite decades of pharmacological research on model species and humans, the mechanisms used by mammalian herbivores to metabolize plant secondary compounds and the genomic basis underlying adaptation to new diets remain poorly understood. This research will investigate the evolution of dietary adaptation and specialization in mammalian herbivores by capitalizing on a dramatic diet change event: the replacement of juniper (Juniperus spp.) and cactus (Opuntia spp.) with creosote bush (Larrea tridentata) in the diets of herbivorous woodrats. The project has three goals: 1) Identify genomic changes associated with a radical dietary shift in Neotoma lepida. 2) Test for the repeated involvement of similar genetic pathways for specialization on creosote diets in N. bryanti. 3) Characterize the transcriptomic response of parental and hybrid populations of N. lepida and N. bryanti to a creosote diet. The proposed work leverages modern evolutionary genomic approaches to address a long-standing question in physiological ecology: which mechanisms are important in the processing of toxic diets? The project will lead to a deeper understanding of the responses of organisms to changes in the environment, including fundamental information at the genomic level about how mammalian herbivores adapt to dietary toxins. The project specifically tests whether the same genomic regions are under selection in two species that independently evolved the ability to specialize on creosote diets. An interactive display about the ecology of woodrats and their importance to society will be developed in collaboration with the Utah Museum of Natural History. Genomic tools will be developed that will be useful to the broader scientific community. In addition, the PIs will mentor students (high school through graduate) and postdocs in physiological genomics research on non-model species.

在每一餐中，以植物（食草动物）为食的动物，如鹿、牛和兔子，都面临着被食物中自然产生的有毒化学物质中毒的可能性。然而，食草动物如何处理天然毒素仍然知之甚少。例如，对于控制动物处理植物中潜在有毒化合物的能力的特定基因，我们所知甚少。为了解决这些基本问题，这项研究将把重点放在一个巨大的饮食变化上：木鼠通常吃杜松和仙人掌，但在美国西南部的几个种群已经转向了木酚油灌木的饮食。木馏油灌木产生的天然毒素与杜松和仙人掌截然不同，因此特殊的木鼠种群必须以不同于杜松和仙人掌为食的食物排毒。该项目的目标是确定与木鼠以有毒的木酚油灌木为食的能力有关的dna水平的变化。这个项目将开发新的基因组工具，这将对更广泛的科学界有用。更好地了解动物如何处理毒素也可以影响人类和其他动物的药物开发决策，并影响喂养选择，以提高牛等自由放养家养食草动物的产量。这项工作的结果将通过犹他州自然历史博物馆关于木鼠生态的互动展示向公众传播。尽管对模式物种和人类进行了数十年的药理学研究，但哺乳动物食草动物代谢植物次生化合物的机制以及适应新饮食的基因组基础仍然知之甚少。本研究将通过利用一个戏剧性的饮食变化事件来研究哺乳动物食草动物饮食适应和专业化的进化：在食草木鼠的饮食中，桧（Juniperus spp.）和仙人掌（Opuntia spp.）被木腐油灌木（Larrea tridentata）取代。该项目有三个目标：1)确定与瘦体瘤（Neotoma lepida）饮食变化相关的基因组变化。2)测试布氏北蝽对杂酚油食性的专业化的相似遗传途径的重复参与。3)研究了疏鳞芸蓟马亲本和杂交种群对杂酚油饮食的转录组反应。提出的工作利用现代进化基因组方法来解决生理生态学中一个长期存在的问题：哪些机制在有毒饮食的加工中是重要的？该项目将使人们更深入地了解生物体对环境变化的反应，包括在基因组水平上了解哺乳动物食草动物如何适应饮食毒素的基本信息。该项目专门测试了两个独立进化出对杂酚油饮食的能力的物种是否有相同的基因组区域在选择中。关于木鼠生态及其对社会的重要性的互动展示将与犹他州自然历史博物馆合作开发。基因组工具将被开发出来，对更广泛的科学界有用。此外，pi将指导学生（从高中到研究生）和博士后进行非模式物种的生理基因组研究。