Epigenetic Variation and Inheritance

基因组以遗传和表观遗传两种方式编码信息。遗传信息包含在基因组的核苷酸序列中，而表观遗传信息则包含在其他地方，通常是核苷酸或染色质的修饰。表观遗传信息以差异DNA甲基化和替代染色质包装的形式影响对潜在遗传信息的获取，从而在基因表达的调节中发挥核心作用。这个项目的重点是表观遗传信息的变异，以及这种变异对一代到下一代遗传的影响程度。这个项目的动力是观察改变拟南芥胞嘧啶甲基化的影响。在这种植物中，胞嘧啶甲基化的减少导致表观遗传信息的稳定遗传变异。这种变异反过来又在整个生物体水平上产生异常表型。该项目包括两个主要部分。首先是研究DNA低甲基化诱导的矮化缺陷的分子基础，bal是由表观遗传改变引起的，导致病原体抗性基因的转录升高。第二个目标是确定在更自然的条件下（即在没有破坏适当表观遗传修饰的突变的情况下）产生的表观遗传变异的流行程度。为了建立这一模式物种表观遗传变异的基线，研究者将研究不同拟南芥品系之间替代表观遗传等位基因的发生。了解基因中核苷酸修饰和染色体包装的影响对理解遗传至关重要。这个项目将有助于科学界在这方面的努力。

Genomes encode information in two ways, genetically and epigenetically. Genetic information is that contained in the nucleotide sequence of the genome, whereas epigenetic information is that contained elsewhere, typically in modifications to the nucleotides or to the chromatin. Epigenetic information in the form of differential DNA methylation and alternative chromatin packaging influences access to the underlying genetic information and thereby plays a central role in the modulation of gene expression. This project focuses on variation in epigenetic information and the extent to which this variation can affect inheritance from one generation to the next. The impetus for this project was the observation of the effects of altering cytosine methylation in Arabidopsis thaliana. In this plant, reduction in cytosine methylation leads to stable inherited variation in epigenetic information. This variation, in turn, generates abnormal phenotypes at the whole organism level. The project involves two major components. The first is the investigation of the molecular basis of the DNA hypomethylation-induced dwarfing defect, bal, caused by an epigenetic alteration that leads to elevated transcription of a pathogen resistance gene. The second objective is to determine the prevalence of epigenetic variation generated under more natural conditions (i.e. in the absence of mutations that destroy proper epigenetic modification). To establish a baseline for epigenetic variation in this model species, the investigator will study the occurrence of alternative epigenetic alleles among different Arabidopsis strains.Understanding the influence of modifications to nucleotides in genes and of the packaging of chromosomes is essential to understanding inheritance. This project will help the scientific community in this endeavour.