Epigenetic stability and its evolutionary potential

表观遗传稳定性及其进化潜力

• 批准号: 1556855
• 负责人: Kathleen Donohue
• 金额: $ 127万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556855&HistoricalAwards=false
• 关键词: Epigenetic; stability; its; evolutionary; potential

This study will examine how environmental conditions that alter patterns of gene expression and are passed to offspring can influence the process of evolution. Environmental conditions can cause changes in the characteristics of individuals, including their morphology, physiology, development, and behavior. Such environmental effects can be ephemeral, or they can persist for whole lifespans or even beyond a single generation. Studying such effects is central to our understanding of the process of evolution, especially as it might be affected by climate change. Epigenetics refers to mechanisms that alter how genetic sequences are translated into functional gene products, and certain epigenetic mechanisms have been implicated in environmental effects on the characteristics of individuals. It has been argued that epigenetic modifications that are stable across generations can be an important source of genetic variation upon which natural selection can act, and that such variation may even be non-random with respect to environmental context and adaptive value. This hypothesis raises a number of compelling questions. First, which epigenetic changes are environmentally induced, and do environment-dependent versus independent changes differ in their stability of inheritance? Second, is the stability of epigenetic alterations itself heritable? Third, is the stability of epigenetic modifications adaptive, and if so, under what conditions? Additionally, this project will train students from high school to graduate school and promote international engagement by graduate students and post-doctoral scholars. The research program will use Arabidopsis thaliana to test for natural variation in the stability of genome-wide methylation states within and across generations, to test whether such stability depends on environmental conditions, and to test whether environmentally induced changes in methylation state are more or less stable than methylation that does not respond to environmental conditions. As such, it tests the prediction that environmentally-induced epigenetic changes can be an important source of heritable phenotypic variation that can contribute to adaptive evolution. Second, a QTL analysis of methylation states, their stability, and their environmental reversibility will test whether methylation stability has a genetic basis. It will also provide information on the number of methylation states that are regulated by a given QTL, and it will test whether loci that regulate methylation stability within and across generations are genetically associated with loci that regulate their environmental reversibility/stability. Finally, the research will test whether loci that regulate methylation states and their stability are also associated with adaptively significant phenotypes and with fitness itself under constant and variable environments. This research targets the stability of epigenetic changes as a key phenotype by testing whether epigenetic stability has a heritable genetic basis and whether it is adaptive under stable and variable environments.

这项研究将研究改变基因表达模式并传递给后代的环境条件如何影响进化过程。环境条件会导致个体特征的变化，包括形态、生理、发育和行为。这样的环境影响可能是短暂的，也可能持续一生，甚至超过一代人。研究这种影响是我们理解进化过程的核心，特别是因为它可能会受到气候变化的影响。表观遗传学是指改变遗传序列如何转化为功能基因产物的机制，某些表观遗传学机制被认为与环境对个体特征的影响有关。有人争辩说，世代稳定的表观遗传修饰可能是自然选择作用于其上的遗传变异的一个重要来源，而且这种变异甚至可能是关于环境背景和适应价值的非随机的。这一假设提出了许多令人信服的问题。首先，哪些表观遗传变化是由环境引起的，环境依赖变化与独立变化在遗传稳定性方面是否存在差异？第二，表观遗传变化的稳定性本身是可遗传的吗？第三，表观遗传修饰的稳定性是适应性的吗？如果是，在什么条件下？此外，该项目将培训从高中到研究生的学生，并促进研究生和博士后学者的国际参与。该研究计划将使用拟南芥来测试整个基因组甲基化状态的稳定性在世代内和世代之间的自然变异，测试这种稳定性是否依赖于环境条件，以及测试环境引起的甲基化状态的变化是否比不响应环境条件的甲基化更稳定。因此，它检验了这样一种预测，即环境诱导的表观遗传变化可能是可遗传表型变化的重要来源，有助于适应性进化。其次，对甲基化状态及其稳定性和环境可逆性的QTL分析将检验甲基化稳定性是否有遗传基础。它还将提供由给定QTL调控的甲基化状态数量的信息，并将测试调节世代内和世代间甲基化稳定性的基因座是否与调节其环境可逆性/稳定性的基因座遗传相关。最后，这项研究将测试调节甲基化状态及其稳定性的基因座是否也与适应性显著的表型以及在恒定和可变环境下的适应性本身有关。本研究通过测试表观遗传稳定性是否具有可遗传的遗传基础，以及表观遗传稳定性是否适应稳定和变化的环境，将表观遗传变化的稳定性作为关键表型。