Epigenetic Variation and Inheritance

基因组以两种方式编码信息，遗传和表观遗传。遗传信息是包含在基因组核苷酸序列中的信息，而表观遗传信息是包含在其他地方的信息，通常是在核苷酸或染色质的修饰中。以差异DNA甲基化和替代染色质包装为形式的表观遗传信息影响对潜在遗传信息的获取，从而在基因表达的调控中发挥核心作用。这个项目的重点是表观遗传信息的变异，以及这种变异可以影响一代又一代遗传的程度。该项目的推动力是对改变拟南芥胞嘧啶甲基化的影响的观察。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。这种变异反过来会在整个生物体水平上产生异常的表型。该项目包括两个主要组成部分。第一个是对DNA低甲基化诱导的矮化缺陷(BAL)的分子基础的研究，该缺陷是由表观遗传改变导致病原菌抗性基因转录升高引起的。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率。为了在这个模式物种中建立表观遗传变异的基线，研究者将研究不同拟南芥品系之间的替代表观遗传等位基因的出现。了解基因中核苷酸的修饰和染色体包装的影响对于理解遗传是至关重要的。该项目将帮助科学界开展这项工作。

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.