Epigenetic stability and its evolutionary potential

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。环境条件可以引起个体特征的变化，包括形态、生理、发育和行为。这种环境影响可能是短暂的，也可能持续整个生命周期，甚至超过一代人。研究这些影响是我们理解进化过程的核心，特别是因为它可能受到气候变化的影响。表观遗传学是指改变基因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与环境对个体特征的影响有关。有人认为，代代稳定的表观遗传修饰可能是自然选择所起作用的遗传变异的重要来源，而且这种变异甚至可能是非随机的，与环境背景和适应价值有关。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环境诱导的，环境依赖性和独立变化在遗传稳定性上是否存在差异？第二，表观遗传改变本身的稳定性是可遗传的吗？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，该项目将培养从高中到研究生院的学生，并促进研究生和博士后学者的国际参与。该研究项目将使用拟南芥来测试代内和代间全基因组甲基化状态稳定性的自然变化，测试这种稳定性是否取决于环境条件，以及测试环境诱导的甲基化状态变化是否比不受环境条件影响的甲基化更稳定。因此，它验证了这样一种预测，即环境诱导的表观遗传变化可能是可遗传表型变异的重要来源，可以促进适应性进化。其次，甲基化状态、稳定性和环境可逆性的QTL分析将检验甲基化稳定性是否具有遗传基础。它还将提供由给定QTL调控的甲基化状态数量的信息，并将测试在代内和代间调控甲基化稳定性的位点是否与调控其环境可逆性/稳定性的位点存在遗传关联。最后，该研究将测试调节甲基化状态及其稳定性的位点是否也与适应显著的表型以及在恒定和可变环境下的适应性本身有关。本研究将表观遗传变化的稳定性作为一种关键表型，通过检测表观遗传稳定性是否具有可遗传的遗传基础，以及在稳定和可变环境下是否具有适应性。

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.