DISSERTATION RESEARCH: Surviving habitat loss: Physiological and evolutionary basis underlying tolerance to deforestation

论文研究：幸存的栖息地丧失：容忍毁林的生理和进化基础

• 批准号: 1404527
• 负责人: Elizabeth Hadly
• 金额: $ 2.09万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404527&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Surviving; habitat; loss

Tropical deforestation reshapes biological communities, benefitting some species, while pushing others towards local extinction. This research will examine the ecological and evolutionary underpinnings of tolerance to deforestation by focusing on the genetics of two closely related Central American frog species. Along with climate change and disease, habitat loss is pushing numerous amphibian species towards extinction. Understanding the biochemical basis for thermal adaptation is a crucial area of research given the multifaceted ways that humans are heating local, regional, and global climates. This research will inform conservation outcomes by providing insight into the reasons that some species are capable of bucking this global trend. The project also will involve the training of a graduate student and undergraduates, including individuals from groups that are underrepresented in the sciences.The researchers will study two species in the genus Craugastor that differ in their tendency to live in forested and deforested areas. Their previous research identified thermal tolerance as the primary factor explaining whether a species can survive in warmer, deforested areas. They will subject both species to forest- or pasture-like temperature regimes, and then uses Illumina-based RNA sequencing to test whether interspecific differences in constitutive expression and capacity to upregulate thermal stress tolerance genes (e.g., heat shock proteins) correspond to habitat affinity. They can thus begin to assess how gene regulation facilitates survival in deforested habitats. While differential expression may facilitate survival, structural differences (i.e., in protein coding sequence) also likely play a role. They will compare sequence data between species to scan for signatures of adaptation by employing both conventional molecular evolutionary tests for positive selection (i.e., dN/dS), as well as developing a novel structure-based approach that examines how changes at the DNA level are expected to alter protein stability at warm temperatures. Using protein homology modeling and RNA sequence data, they will test the hypothesis that proteins in the deforestation-tolerant species exhibit increased thermal stability. Because conventional methods of testing for positive selection are prone to false negatives, the use of a structure based, hypothesis-testing framework will substantially increase the detection of thermal adaptation. This study will place ecological changes caused by human activity in a macroevolutionary context, and provide a specific structural hypothesis to detect thermal adaption in an increasingly warm, human-dominated biosphere.

热带森林砍伐重塑了生物群落，使某些物种受益，同时又将其他物种推向局部灭绝。这项研究将通过关注两种密切相关的中美洲青蛙物种的遗传学，研究对森林砍伐耐受性的生态和进化基础。除了气候变化和疾病之外，栖息地的丧失正在将许多两栖动物物种推向灭绝。鉴于人类以多种方式加热局部、区域和全球气候，了解热适应的生化基础是一个重要的研究领域。这项研究将通过深入了解某些物种能够逆这一全球趋势的原因来为保护结果提供信息。该项目还将包括对研究生和本科生的培训，包括来自科学领域代表性不足的群体的个人。研究人员将研究Craugastor属中的两个物种，它们在森林和森林砍伐地区的生活倾向不同。他们之前的研究发现耐热性是解释一个物种能否在温暖的森林砍伐地区生存的主要因素。他们将这两个物种置于类似森林或牧场的温度条件下，然后使用基于 Illumina 的 RNA 测序来测试组成型表达和上调热应激耐受基因（例如热休克蛋白）的能力的种间差异是否与栖息地亲和力相对应。因此，他们可以开始评估基因调控如何促进森林砍伐的栖息地的生存。虽然差异表达可能有助于生存，但结构差异（即蛋白质编码序列）也可能发挥作用。他们将比较物种之间的序列数据，通过采用传统的正选择分子进化测试（即 dN/dS）来扫描适应特征，并开发一种基于结构的新型方法来检查 DNA 水平的变化将如何改变温暖温度下的蛋白质稳定性。他们将使用蛋白质同源模型和 RNA 序列数据来检验这一假设，即耐毁林物种中的蛋白质表现出更高的热稳定性。由于传统的正选择测试方法容易出现假阴性，因此使用基于结构的假设检验框架将大大增加热适应的检测。这项研究将把人类活动引起的生态变化置于宏观进化的背景下，并提供一个特定的结构假设来检测日益温暖的、人类主导的生物圈中的热适应。